During the period 2014 to 2025 Sunfish has supported four scientific research groupings, scientific papers of which which have been published in peer-reviewed scientific journals by the Sunfish Scientific Officer, Dr Barry Pollock. All projects were of high priority for fisheries research as determined by Sunfish. In these projects recreational fishers and others (citizen science contributors) were engaged, and the projects were funded by these volunteers. No government funds were sought or provided. A total of six scientific papers and a book has been produced, and another on Queensland snapper is in progress. This demonstrates the willingness of Sunfish, its associated recreational fishers, and others to contribute to research and scientific knowledge. The research topics are saddleback deformities, flathead, snapper, and luderick. Copies of the scientific papers are provided. In the period 2014 to 2022 Sunfish has supported five scientific research projects which have been published in peer-reviewed scientific journals by the Sunfish Scientific Officer, Dr Barry Pollock. In these projects recreational fishers have made major voluntary contributions, and the projects were fully funded by volunteer recreational fishers. No government funds were sought or provided. This demonstrates the willingness of Sunfish, its associated recreational fishers, and recreational fishers generally to contribute to research and scientific knowledge of the fish they seek to catch.

Summaries of the findings of these five scientific research projects are given below. Details for obtaining the full papers are also given. A huge amount of time and effort has been provided on a voluntary basis to carry out and complete these scientific studies. All those who assisted, including staff at the Ecosciences Precinct, University of Queensland, Fisheries Queensland and NSW Fisheries, are sincerely thanked.

By B.R. Pollock
Sunfish Queensland Incorporated, Brisbane, Australia

Summary
The aim of this study was to determine if saddleback syndrome (SBS) in a wild population of yellowfin bream ( Acanthopagrus australis) was the result of a developmental defect or caused by physical injury. Information was collected in 2012 on the incidence of SBS and other abnormalities in this species in Moreton Bay, Australia. Abnormalities in adult fish (>250 mm Total Length, TL) with SBS (n = 47) were compared with those without SBS (n = 30). A sample of juvenile fish (n = 404) was checked for the presence of SBS. The results show that scale loss, scale pattern misalignment, lateral line fracture and pectoral fin abnormality were closely associated with SBS. SBS was uncommon (<2%) in juveniles <70 mm TL, but common (>12%) in the larger juveniles (70–215 mm TL). These results, together with the findings that scale loss associated with SBS in adult fish occurred in the range 80–245 mm back-calculated TL, indicate that SBS and the related abnormalities in yellowfin bream are a result of physical injuries to larger juveniles (>70 mm TL). The reduction in the incidence of SBS from approximately 12% in the larger juveniles to 5% in adults is evidence of mortality associated with SBS.

Introduction
In recent years, fishers in Moreton Bay, Australia and nearby regions have reported a deformity on the dorsal margin of yellowfin bream, Acanthopagrus australis (Family Sparidae). This has been identified as a typical saddleback syndrome (SBS), and its occurrence has been as high as 5–10% of individuals in yellowfin bream catches (Diggles, 2013). A stakeholder workshop involving researchers, fishery managers and fishers was held in January 2012 to discuss the extent of the problem, possible causes and future research directions (Campbell and Landers, 2013). The definition of SBS is an abnormality of the dorsal fin and profile, lacking one to all of the dorsal spines, accompanied by shape, number and position abnormalities of associated pterygiophores (Koumoundouros et al., 2001). Deformity and loss of dorsal spines, pterygiophores and neural spines in fish with SBS have been described in several species including yellowfin bream (Diggles, 2013). SBS in wild populations of fish has been attributed to several causes including physical injuries (James and Badrudeen, 1968) such as injuries caused by predatory fish (Almatar and Chen, 2010). Other studies have identified developmental defects associated with unsuitable water conditions, including chemical contamination (Browder et al., 1993; Lemly, 1993; Jawad and Al-Mamray, 2012). There are also studies showing that SBS can be an inherited characteristic (Tave et al., 1983).

The yellowfin bream is endemic to Australia and restricted to the east coast, where it occurs in estuaries and coastal waters extending from tropical to temperate regions. It is extensively fished both recreationally and commercially throughout its range, with Moreton Bay being one of the most productive areas (Williams, 2002; Taylor et al., 2012). The Moreton Bay fishery for yellowfin bream is tightly managed (Queensland Government, 2009, 2012), with restrictions on types of gear that both recreational and commercial fishers may use, limits on the numbers of commercial fishing licences, a bag limit for recreational fishers, and a minimum size of 250 mm total length (TL), which approximates the size at maturity (Pollock, 1982a). The current fisheries monitoring programme and status report classifies yellowfin bream stocks as sustainably fished (Queensland Government, 2010). The population biology of yellowfin bream in Moreton Bay is well understood (Munro, 1945; Blaber and Blaber, 1980; Pollock, 1982a, 1984; Pollock et al., 1983; Morton et al., 1987). Adult yellowfin bream have spawning aggregations at the estuary-ocean interface during winter (June–July); post larvae subsequently settle in estuaries after about 1 month in the plankton (August–September). The juvenile fish grow quickly particularly for the first 3 years.

The aim of the present study was to determine whether SBS in yellowfin bream is a developmental defect or caused by physical injury. To do this, the study investigated the presence of SBS in a wild population of juvenile and adult yellowfin bream, and the association of SBS with other abnormalities, including scale pattern misalignment, scale replacement, and deformities of the lateral line and pectoral fins. Estimates of the size of yellowfin bream when SBS occurs were made by using back-calculations of the total length at scale replacement and by noting changes in the incidence of SBS in juvenile fish of different sizes.

Materials and methods
The study was conducted in southern Moreton Bay, Australia (27° 45 0S; 153°200E) with samples of yellowfin bream with SBS and those without this deformity (Fig. 1a, b) being taken in the region from the Logan River in the North to the Nerang River in the South. These samples came from two sources: adult fish provided by fishing club anglers and juvenile fish collected by the author. On 22 July 2012, at their official weighing-in of catches throughout the sampling area, fishing club anglers provided 47 yellowfin bream with SBS over the legal minimum size (>250 mm TL) that were caught the previous night. Anglers kept approximately 10 additional yellowfin bream with SBS. At this event a total of 86 anglers caught 1170 yellowfin bream over the minimum legal size. A sample of 30 yellowfin bream (>250 mm TL) without SBS was also provided to the study by the anglers as a control sample. A sample of 404 juvenile yellowfin bream less than the legal minimum size (<250 mm TL) was collected in the study area from October to December 2012 using several gear types: baited traps, 600 mm long, 400 mm wide, 200 mm high with two funnel openings and mesh size 20 mm; a cast net (7 m diameter) and a seine both with 20 mm mesh; and lines with baited hooks (sizes 12–20). The majority of juvenile yellowfin bream (n = 398) were caught near the mouth of the Nerang River. The remainder (n = 6) was caught near the mouth of the Logan River. Each of the juvenile fish was measured (TL to the nearest 5 mm) and photographed. These photographs were later examined to determine the presence or absence of SBS.

All adult yellowfin bream obtained on 22 July 2012 (n = 77) were processed the same day whereby each fish was assigned an identifying number, photographed on each lateral surface, measured (TL to the nearest 10 mm), and scale samples (n = 10–12 scales) taken from each side of each fish below the saddleback deformity or from an equivalent location on fish without SBS. During this procedure each fish was examined for fin deformities additional to SBS. Some fish with SBS had pectoral fins that were locked into an abnormal position, approximately perpendicular to the lateral surface (Fig. 2a). Fish without SBS did not have this pectoral fin deformity. The photographs of both lateral surfaces of each of the 77 adult fish sampled were later examined for the presence of scale pattern deformities and lateral line fractures (Fig. 2b). Scale pattern deformity is defined as misalignment in the normal, symmetrical pattern of scale rows on the lateral surface (Browder et al., 1993). A subsample of eight scales from each of the 154 scale samples was cleaned in water and mounted between microscope slides. When dry, the numbers of normal and replacement scales (Fig. 3) in each subsample were identified under magnification and recorded. Measurements to the nearest 1 mm were taken of the scale length and length of the granular section on a typical replacement scale from each scale set (Fig. 4). When both lateral surfaces had replacement scales, the means of the two values of scale length and length of the granular section were calculated. The length of each fish when scales were replaced was back-calculated by the Fraser–Lee method (Duncan, 1980):

Lr ¼ Lg/Ls  (TL-c) + c;

where, Lr is the back-calculated total length (mm) at scale loss, Lg is the length of the granular section on the scale, Ls is the scale radius, TL is the total length (mm). The c value of 10 mm was used, which approximates the length of yellowfin bream when scales are first formed on post larvae (Munro, 1945). Three indices were used to quantify the extent and location of the SBS on each adult fish sampled (n = 47). The relative depth of the deformity into the dorsal margin: Index of SBS depth ¼ Dsbs/Db  100; where Dsbs is the distance from the dorsal margin to the deepest extent of the deformity, and Db is the largest vertical distance from the dorsal margin to the ventral margin (Fig. 5a, b). The relative width of this deformity along the dorsal margin:

Index of SBS width ¼ Wsbs/TL  100;

where Wsbs is the length of the deformity on the dorsal margin, and TL is the total length (Fig. 5a, b)

The relative anterior-posterior position of the deformity on the dorsal margin:

Index of SBS location ¼ Lsbs/TL  100;

where Lsbs is the anterior-posterior distance from the mouth to the deepest part of the deformity (Fig. 5a).

Measurements of Dsbs, Db, Wsbs, and Lsbs were made to the nearest 1 mm.

The Chi-squared test was used to compare the occurrence of SBS in different size-classes of yellowfin bream, and the incidence of scale pattern deformities in SBS fish and those without SBS.

The sampling area in southern Moreton Bay is protected from the Pacific Ocean by South Stradbroke Island, a narrow sand island approximately 20 km in length. The southern sampling area, including the Nerang River, contains numerous waterfront canal developments with dense residential housing, and numerous anchorages for vessels. In the North, including the Logan River, intensive sugar cane agriculture has been carried out adjacent to the shoreline since the 1960s (Gold Coast City Council, 2007). Tides in the area are semi-diurnal with a maximum range of approximately 2 m. The ocean entrances of the Southport Seaway and the Jumpinpin Bar, in association with tidal water movements result in significant flushing of much of the study area (Eyre and McKee, 2002).

Results
In adult yellowfin bream (>250 mm TL), the index of SBS location (Fig. 6) shows that the SBS deformity occurs most frequently on the anterior half of the dorsal margin. The deepest part of the deformity occurs either anterior to the dorsal spines or within the anterior half of the dorsal fin (Fig. 6). The width of the deformity is most commonly 5–10% of the body length, but can be as much as 20% in extreme cases (Fig. 7). Whilst the maximum depth of the deformity may be anterior to the dorsal spines, the deformity extends into the area of the dorsal spines. In all specimens of SBS fish over 250 mm TL observed in this study (n = 47), the dorsal spines were deformed, ranging from deformity of the first dorsal spine only to the deformity or loss of several dorsal spines. In these fish, the SBS depth index (Fig. 8) was slight (1.0 or less) in 13% of the sample, moderate (1.1–5.0) in 76%, and severe (> 5.0) in 11%.

From observations of catches on 22 July 2012, SBS was present in 57 adult fish (> 250 mm TL) from a total catch of 1170 (4.9% of the total catch). Scale pattern deformities occurred on 37 of the 47 fish collected with SBS (79%), comprising 24 fish (51%) with scale pattern deformities on both lateral surfaces, and 13 fish (28%) with this deformity on one lateral surface only. In the control sample of 30 fish without SBS, eight individuals (27%) had scale pattern deformities on one lateral surface; a single specimen (3%) had this deformity on both lateral surfaces. The frequency of occurrence of scale pattern deformity in the control sample of normal fish is 27% compared with 79% in fish with SBS. This difference is highly significant (P < 0.001). Pectoral fin abnormalities occurred in seven of the 47 SBS fish over 250 mm TL (15%), with one of these having the deformity on both pectoral fins. Lateral line fracture occurred in six out of 47 fish with SBS (13%). None of the control sample of adult fish without SBS had pectoral fin abnormalities or lateral line fractures.

Original scales, first laid down at the post larval stage, may be lost and subsequently replaced by new scales (Figs 3 and 4). The replacement scales are distinctive on account of the granular growth area in the central portion of the scale. Replacement scales were much more common in SBS fish compared with those without SBS (Fig. 9). In adult fish with SBS, all specimens (n = 47) had replacement scales on both lateral surfaces at high concentrations (25% or more replacement scales in each scale sample). In adult fish without SBS (n = 30), 60% had low concentrations of replacement scales (< 25% replacement scales in each scale sample), and of these fish, 27% had no replacement scales (Fig. 9).

Based on length back-calculations (Fig. 10), adult fish with SBS exhibit scale loss and replacement at 110–245 mm TL. (mean TL at scale replacement is 160 mm). In the case of yellowfin bream without SBS, scale loss and replacement occurs at 80–175 mm TL, with a mean of 135 mm TL.

Frequency of SBS occurrence in juvenile yellowfin bream increased greatly with size. In the smaller size-class sampled (30–65 mm TL, n = 215), SBS occurrence was low (n = 4, 1.9%). SBS was much more common (n = 23, 12.2%) in the larger juvenile size-class (70–215 mm TL, n = 189). This difference is highly significant (P < 0.0001). The approximate size at which SBS first became common in juvenile fish was 70 mm TL. The difference in occurrence of SBS in the larger juvenile size-class (12.2%), compared with that in adult fish (4.9%) is also highly significant (P < 0.001).

Discussion
The form of SBS on individual fish The frequency distributions of indices for SBS location, width and depth on individual yellowfin bream are all unimodal, with ranges within relatively restricted limits (Figs 6–8). The cause of SBS in yellowfin bream therefore appears to be acting very specifically in terms of the location and extent of the resulting deformity. The skeletal deformities associated with SBS in yellowfin bream are described by Diggles (2013). Radiographs in that study show in a yellowfin bream with mild SBS that skeletal abnormalities comprise pterygiophore deformities and neural spine disorganization. Diggles (2013) also found that a yellowfin bream with severe SBS deformity had the loss of some pterygiophores and severe deformity of the neural spines. From figures of the two specimens in the Diggles (2013) study, it was possible to calculate the SBS depth indices of 0.95 in the case of the specimen with mild SBS, and 5.5 for the specimen with severe SBS. The SBS depth index values, based on a large sample of yellowfin bream with SBS (n = 47) in the present study ranged from 0.8 to 6.5. These findings by Diggles (2013) and by the present study are complementary, and it is reasonable to infer that yellowfin bream with both mild and severe SBS have associated deformities of the pterygiophores and neural spines.

Association of SBS with other abnormalities
Scales in fish are not shed naturally but usually result from an injury. Lost scales in most investigated fish species are replaced quickly (Quilhac and Sire, 1998; Ohira et al., 2007; Vieira et al., 2011). An example of rapid scale replacement is in the marine sea bass, Dicentrarchus labrax, where replacement scales are visible at 3 days after removal and by 6 days the descaled area is covered with new scales. At 21–30 days the newly formed scales appear similar to original scales (Guerreiro et al., 2013). All yellowfin bream with SBS have moderate to severe scale loss. The majority of those without SBS have zero to minor scale loss (Fig. 9). Yellowfin bream with SBS have a significantly higher incidence of scale pattern deformity (approximately 80%), compared with those without SBS (approximately 30%). Both lateral line fracture and pectoral fin deformities are less common overall, but only occur in fish with SBS. Whilst it is possible that pectoral fin abnormalities are due to the way the fish were handled by fishers after capture, the result that these deformities were only observed in SBS fish is evidence that this is a deformity associated directly with SBS.

SBS in yellowfin bream – occurrence and possible cause
In yellowfin bream, SBS first becomes common in large juveniles, a result that corresponds closely with the back-calculations of TL at scale replacement for adult fish with SBS. Based on these findings, SBS and the associated deformities in yellowfin bream are most likely caused by physical injuries to larger juveniles, and not by developmental defects commencing in larval or post larval fish. However, the appearance of the SBS-associated deformities in yellowfin bream without SBS needs explanation. It appears that the overall injury trauma in the case of yellowfin bream consists of a group of associated deformities. The number and severity of these deformities on individual adult yellowfin bream are variable, and may or may not include SBS.

Juvenile yellowfin bream with SBS were collected at both extremities of the study area, a distance of approximately 20 km, although the sample size from the North region was relatively small. Juvenile yellowfin bream in this region undertake only small-scale movements up to a maximum of 6 km (Pollock, 1982b). This indicates that SBS is acquired by juvenile fish at multiple locations within the study area. Adult fish are much more mobile than the juveniles. It is therefore expected that the adult fish with SBS could have moved considerable distances from where they acquired SBS as juveniles. The present study did not specifically investigate causes of physical injuries that could result in SBS and ssociated deformities, however the most likely are: escapement from piscivorous birds or predatory fish, ectoparasite injuries and removal or escapement from fishing gear. In Moreton Bay the most abundant piscivorous birds likely to prey on demersal species such as yellowfin bream are cormorants (Family Phalacrocoracidae) and pelicans (Family Pelecanidae) (Simpson and Day, 1998). Several predatory fish species are abundant in the same habitat as juvenile yellowfin bream, most notably flathead ( Platycephalus fuscus), tailor ( Pomatomus saltatrix), and mangrove jack ( Lutjanus argentimaculatus) (Grant, 1975). No ectoparasites were observed on any of the yellowfin bream taken in the present study, hence this is unlikely to be the cause of injuries in this case.

Several studies of yellowfin bream and other species show that physical damage may occur as a result of fishing operations and the subsequent escape or release of the fish. Halliday et al. (2001) describe the capture of yellowfin bream by commercial fishers in gill-nets used north of Moreton Bay; about half of the yellowfin bream caught in that study were discarded as being under the legal minimum size. In the case of enmeshed yellowfin bream, the fish were mainly removed tail first from the net, and released. Several studies have reported injuries to fish as a result of net damage (Chopin and Arimoto, 1995). The study of gill-netting in inshore waters in New Zealand by Hickford and Schiel (1996) categorises the resulting injuries in order of severity: chafing or scale loss, minor lesions and fin damage, major lesions and flesh loss, and loss of skeletal material. These injuries are consistent with SBS and associated abnormalities observed on yellowfin bream in the present study.

Mortality associated with SBS and future research
The reduction in the incidence of SBS in the larger juveniles compared with adult yellowfin bream (from 12.2% to 4.9%) is highly significant and consistent with a differential ortality of juvenile fish with SBS. However, this interpretation needs to acknowledge the possibility of annual and site-specific variability of SBS. In eastern Australia, the yellowfin bream fishery is very important from both social and economic perspectives. Whilst the yellowfin bream fishery has been well managed and monitored by the relevant fisheries agencies, further research is important to fully understand the exact cause and impacts of SBS and associated abnormalities on yellowfin bream stocks. In particular, future research is needed regarding the variability of SBS in both juvenile and adult yellowfin bream in different locations and years, with emphasis on estimating mortalities associated with SBS. Further research is also needed on the injuries caused by catching and releasing yellowfin bream that are under the legal minimum size.

Acknowledgements
Matthew Campbell assisted with the collection of juvenile fish under General Fisheries Permit Number 147714 (Queensland fisheries legislation), and provided helpful suggestions throughout the course of the study. Ben Diggles suggested the control sample of adult fish and discussed interpretations of some of the findings. Jason McGilvray and Glenys Pollock helped photograph the scales and prepare the figures, respectively. David Bateman, Martin Cowling and Laurie Stone arranged for the provision of fish samples from anglercatches and assisted with the sampling of juveniles. Bob Pearson kindly reviewed the manuscript.

*The editorial office has received comments on the manuscript (Dr. Diggles), offering a different potential origin of the saddleback syndrome (e.g. defects during ontogenetic development). Although such causes can not be totally outruled, it is highly likely that in the present study these deformaties were caused by injury. Controversial views stimulate scientific debate and it is for this reason why I provide two recent references for further reading: (a) Pollock BR (2015). Comments on Saddleback deformities in yellowfin bream from South-East Queensland by Diggles (2013). JFD doi:10.1111/jfd.12334 (early view); (b) Diggles BK (2015). Reply to Pollock (2014) Comments on Saddleback deformities in yellowfin bream from South East Queensland by Diggles (2013). JFD doi:10.1111/jfd.12339 (early view).
Harald Rosenthal, Editor-in-Chief

Comments by an anonymous referee on initial paper: I believe saddleback syndrome may be caused by fish being captured in gillnets as juveniles and healing externally as they grow. I believe thorough histological investigation is required, as suggested by Pollock.

Barry Pollock
Sunfish Queensland, 25 Uther Street, Brisbane, Queensland, 4152, Australia.

ABSTRACT
The yellowfin bream A. australis supports an important commercial net and angling fishery on the east coast of Australia. Saddleback, a deformity of the dorsal fin and profile, occurs in this species, with the occurrence of fish with saddleback being as high as 10% in some areas. The present study provides new information and analysis of causation of the saddleback deformity in the yellowfin bream fishery. Lateral line scale regeneration due to injury, and soft tissue abnormalities indicative of deep wounding are present in yellowfin bream with saddleback. X-ray images of the entire skeleton of specimens with saddleback were also examined. An unpublished government report on chemical residues in saddleback and normal yellowfin bream is appended and discussed. The absence of both chemical residues, and lack of other skeletal deformities in yellowfin bream with saddleback provide indirect evidence of physical injury as the cause of saddleback in this case. The role of discarding of meshed yellowfin bream, which are smaller than the legal minimum size, as causation of the saddleback deformity is evaluated..

Barry Pollock
a Sunfish Queensland, 25 Uther Street, Brisbane, Queensland-4152, Australia.

ABSTRACT
The saddleback deformity, an abnormality of the dorsal fin and profile, lacking one to all of the dorsal spines, accompanied by shape, number and position abnormalities of associated pterygiophores, has been reported in teleosts under culture conditions and in the wild in many locations throughout the world, including North and South America, Asia, Australia, Europe, India and the Middle East. A unique global hotspot for saddleback deformities in wild teleosts is the southeast Queensland Australia coastal region between 26° S and 28° S. At this location the incidence of saddleback has been relatively stable but very high at about 10% of individual teleosts taken in the associated fishery since 1997. Opinions on causation have focused on two possibilities, a developmental defect associated with water pollution or a physical injury. The range of skeletal deformities is vastly different in cultured teleosts compared with those occurring in the wild. There is now mounting evidence that physical injury is causing saddleback in teleosts in southeast Queensland Australia. Such injury could be caused by predatory behaviour of piscivorous fish or birds, parasites, or escapement or release from fishing nets and other fishing gear. Population mortality rates associated with saddleback in southeast Queensland are unknown, but expected to be high. The high level of occurrence of saddleback in teleosts in southeast Queensland Australia together with the good understanding of their fisheries biology

POLLOCK, B.R.

Dusky flathead Platycephalus fuscus form seasonal spawning aggregations where estuaries meet the ocean in eastern Australia. The present study at Jumpinpin in south Queensland shows that dusky flathead have a protracted spawning period with serial spawning during summer (November to April). They are rudimentary hermaphrodites with sex determined at an early juvenile stage. Sex ratios are skewed with males most common in the smaller size-classes (< 50 cm TL). Mid-sized females (45 cm - 69 cm TL) dominate the production of eggs due to their abundance in the spawning aggregation. Within the female component of the spawning aggregation, the occurrence of individuals exceeding the current maximum size limit of 75 cm TL is low (2.6%). Parasitic nematodes (philometrids) occurred in 8% of ovaries. Degenerated ovaries, in which atretic oocytes are common, are present in half of the very large females (70 cm — 75cm TL) examined. The current minimum size restriction of 40 cm TL for dusky flathead provides protection for 73% of males and 15% of females within the spawning aggregation.

Abstract
The aim of the present study is to examine developmental changes of oocytes and ovaries of a wild population of dusky flathead Platycephalus fuscus (Cuvier, 1829). This fish is endemic to the east coast of Australia where it inhabits estuaries and coastal waters. It is extensively fished throughout its range. It is a serial spawning teleost, capable of producing vast numbers of externally fertil- ised eggs in batches over a protracted annual spawning period. Successful egg production, as indicated by the presence of hydrated oocytes and post ovulatory follicles, is commonly observed in small and mid-size females (35cm–65cm Total Length; 2-6 years old) which numerically dominate the female component of the spawning aggregation. Oocyte atresia, at various levels, commences at the vitellogenic oocyte stage, and occurs in all mature fish during the spawning period. Mass oocyte atresia and degenerate ovaries were commonly observed in large fish (>70 cm Total Length and 7 years old), indicating that reproductive senescence occurs after females reach this size.

The NSW paper has been highly praised by international scientists/

Barry R. Pollock

Abstract
This study is based on monthly samples of dusky flthead ( n = 87) in the size range 40 cm TL (total length) to 75 cm TL, collected by angling methods from upper estuarine areas in southern Queensland during the spawning period (September to April). Ovaries at two stages of development were identifid by macroscopic and microscopic examination: unyolked (translucent) ovaries, the most common form, in which oocytes are undergoing mass atresia up to α stage; and yolked (vitellogenic) ovaries which are also undergoing mass atresia to both α and β stages. An unusual fiding is mass atresia of previtellogenic oocytes, showing multiple irregular vacuoles within the oocyte cytoplasm, which commonly occurs in both ovary types. Mature males have testes that are small and degraded. No ripe or running ripe gonads were found in the upper estuarine fih during the spawning period. It is concluded that these dusky flthead are not spawning, in contrast to the spawning aggregation fih at the Jumpinpin estuarine/oceanic interface which is 10 km to 20 km distant from the study site. Given the major differences in gonads and oocytes between spawning aggregation fih and those from upper estuarine areas, it is unlikely that mixing of the two subpopulations occurs during the spawning period. A review of size at maturity of dusky flthead estimated that L50 (length at which 50% of the size class has reached maturity) for females is 35 cm TL to 39 cm TL, and 30 cm TL to 34 cm TL for males.

History, Stock Assessments and Management Second Edition. Update, 2024
Barry Pollock
A Sunfish open access publication

econd edition update of this book. The first edition of this book was published in 2022. Since then another stock assessment is due by Fisheries Queensland (Northrop et al 2024 under internal peer review). The Queensland snapper management advisory committee has not met since February 2022 and a harvest strategy for the Queensland snapper fishery has not been determined. This second edition of the book on the Queensland snapper fishery provides an update to mid-2024.

New Queensland snapper research

A new snapper research project on their reproductive biology in southern Queensland commenced in September 2025 and will be completed in August 2026. This is a joinr study between Sunfish (Dr Barry Pollock) and the University of Queensland (Dr Daryll Whitehead). Monthly samples will be taken under fisheries and marine parks permits by Dr Barry Pollock. Citizen science contributers will take large snapper in accord with the legislation, and under the National code of conduct for recreational fishing. Little is known of the reproductive biology of Queensland snapper. This project will determine size at maturity, spawning times and locations, macroscopic and microscopic features of ovaries and testes, whether sex inversion or rudimentary hermaphrodism occurs, and implications for management of the Queensland snapper fishery.

Luderick
This scientific study is one of the few which significantly correlates decreasing abundance with increasing water temperature for a single fish species on the Australian east coast.

B. R. Pollock
Sunfish Queensland Incorporated, PO Box 3013, Warner, Qld 4500, Australia.

Abstract.
During the past two decades there has been a major decline in the luderick (Girella tricuspidata) population and fishery in the coastal areas of southern Queensland, Australia. This region is the northern limit of the range of luderick. An analysis of annual time series information from the luderick fishery and from sea surface temperature records from 1976 to 2015 found a moderate and significant negative correlation (Pearson r ¼ 0.39, P , 0.05) between water temperature and population abundance in southern Queensland. Previous studies of juvenile and adult luderick indicate their sensitivity to elevated water temperature at the northern limit of their range, further supporting the hypothesis that declines in population abundance of luderick in southern Queensland are associated with increased water temperature. Other possible factors for the luderick population decline (overfishing and habitat loss) are discussed. Any future increases in coastal water temperatures in eastern Australia may result in further southward shifts of the luderick population, and may have similar effects on other fish species that have their northern range limits in southern Queensland.