Assessment of the barramundi (Lates calcarifer) fishery in the Southern Gulf of Carpentaria, Queensland, Australia.

Wild-capture barramundi (Lates calcarifer) forms the basis of important commercial, recreational and customary Indigenous fisheries in Queensland, with an estimated harvest of about 700 tonnes in 2015 (Saunders et al. 2016). For stock status assessment, barramundi in Queensland are considered to consist of seven genetically distinct populations. Within the Gulf of Carpentaria (GoC), there are two genetic stocks split at around 13⁰ S - a Northern Gulf of Carpentaria stock and a Southern Gulf of Carpentaria stock. The Gulf of Carpentaria Inshore Fin Fish Fishery harvests barramundi from both these stocks, but the current assessment focuses on the Southern Gulf of Carpentaria (Southern GoC) barramundi stock, which produces, on average, greater than 50% of the annual commercial harvest of barramundi in Queensland and was listed as transitional-depleting in the 2016 Status of Australian Fish Stocks report (Saunders et al. 2016)

Unique behavioral and neurochemical effects induced by repeated adolescent consumption of caffeine-mixed alcohol in C57BL/6 mice.

The number of highly caffeinated products has increased dramatically in the past few years. Among these products, highly caffeinated energy drinks are the most heavily advertised and purchased, which has resulted in increased incidences of co-consumption of energy drinks with alcohol. Despite the growing number of adolescents and young adults reporting caffeine-mixed alcohol use, knowledge of the potential consequences associated with co-consumption has been limited to survey-based results and in-laboratory human behavioral testing. Here, we investigate the effect of repeated adolescent (post-natal days P35-61) exposure to caffeine-mixed alcohol in C57BL/6 mice on common drug-related behaviors such as locomotor sensitivity, drug reward and cross-sensitivity, and natural reward. To determine changes in neurological activity resulting from adolescent exposure, we monitored changes in expression of the transcription factor ΔFosB in the dopaminergic reward pathway as a sign of long-term increases in neuronal activity. Repeated adolescent exposure to caffeine-mixed alcohol exposure induced significant locomotor sensitization, desensitized cocaine conditioned place preference, decreased cocaine locomotor cross-sensitivity, and increased natural reward consumption. We also observed increased accumulation of ΔFosB in the nucleus accumbens following repeated adolescent caffeine-mixed alcohol exposure compared to alcohol or caffeine alone. Using our exposure model, we found that repeated exposure to caffeine-mixed alcohol during adolescence causes unique behavioral and neurochemical effects not observed in mice exposed to caffeine or alcohol alone. Based on similar findings for different substances of abuse, it is possible that repeated exposure to caffeine-mixed alcohol during adolescence could potentially alter or escalate future substance abuse as means to compensate for these behavioral and neurochemical alterations. © 2016 Robins et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Epigenetics underpins phenotypic plasticity of protandrous sex change in fish

Abstract Phenotypic plasticity is an important driver of species resilience. Often mediated by epigenetic changes, phenotypic plasticity enables individual genotypes to express variable phenotypes in response to environmental change. Barramundi (Lates calcarifer) are a protandrous (male-first) sequential hermaphrodite that exhibits plasticity in length-at-sex change between geographic regions. This plasticity is likely to be mediated by changes in DNA methylation (DNAm), a well-studied epigenetic modification. To investigate the relationships between length, sex, and DNAm in a sequential hermaphrodite, here, we compare DNAm in four conserved vertebrate sex-determining genes in male and female barramundi of differing lengths from three geographic regions of northern Australia. Barramundi first mature as male and later sex change to female upon the attainment of a larger body size; however, a general pattern of increasing female-specific DNAm markers with increasing length was not observed. Significant differences in DNAm between males and females of similar lengths suggest that female-specific DNAm arises rapidly during sex change, rather than gradually with fish growth. The findings also reveal that region-specific differences in length-at-sex change are accompanied by differences in DNAm and are consistent with variability in remotely sensed sea temperature and salinity. Together, these findings provide the first in situ evidence for epigenetically and environmentally mediated sex change in a protandrous hermaphrodite and offer significant insight into the molecular and ecological processes governing the marked and unique plasticity of sex in fish

Understanding environmental and fisheries factors causing fluctuations in mud crab and blue swimmer crab fisheries in Northern Australia to inform harvest strategies

The current project investigated relationships between environmental factors and harvests of crabs in the Gulf of Carpentaria (GoC), northern Australia. This was in response to industry and managerial concerns about consistent declines in harvests of GoC Giant Mud Crab (Scylla serrata). In the orthern Territory (NT), declines occurred between 2009 and 2016, whilst in Queensland (Qld), declines occurred between 2013 and 2016. The declines occurred despite different management arrangements (e.g. NT harvests females, whereas Qld does not), suggesting common environmental factors were involved

Contribution of three rivers to floodplain and coastal productivity in the Gulf of Carpentaria: Finfish catch and growth

Barramundi were used as an indicator species for the effects of river flows on estuaries because they use a variety of aquatic habitats (marine to freshwater) and are an iconic fisheries species of significance in northern Australia. The Fisheries Queensland commercial catch logbook and monitoring data for length, age and reproductive data provide a long-term data series of this estuarine-dependent species in the Gulf of Carpentaria (GoC)

Towards an Initial Quota for the Queensland Mud Crab Fishery

Mud crabs in Queensland (principally Scylla serrata) are captured by baited pots. They are found mostly in estuaries and adjacent foreshores. Their populations are spatially variable and separated between the east coast and the Gulf of Carpentaria. No previous stock assessment has evaluated the sustainability of mud crab harvests in Queensland. This stock assessment is new, using the modified catch-MSY method of Haddon et al. (2018) from Martell and Froese (2013). The model used data from 1988/89 to 2017/18. This comprised of annual commercial harvests, and an estimate of recreational harvest derived from state-wide phone-diary surveys. The assessment provides estimates of exploitable biomass in 2017-18 and recommends Total Allowable Catches for the east coast and Gulf of Carpentaria stocks. The recommendations considered the biological sustainability of the stocks. Other objectives, such as social and economic, were not addressed in the analysis. However, they are important considerations when setting limits on harvests

Stock assessment of the barramundi (Lates calcarifer) fishery in Queensland, Australia. May 2019

Lates calcarifer (barramundi) is a diadromous species consisting of seven genetic stocks in Queensland. All stock regions were assessed, except for the lesser fished regions of Princess Charlotte Bay and the South-East Coast, which had insufficient information. The Queensland stocks are genetically different to the stocks of the Northern Territory. Barramundi are relatively long lived with some specimens reaching 20 to 35 years. They mature (mostly) as males first before changing into females, and move between salt and freshwater. Barramundi populations are environmentally driven, with river-flow affecting their growth, survival, and catchability. Recent commercial catch in 2017 was around 839 tonnes in all of Queensland. With respect to the five genetic stocks considered in this assessment, the commercial catch in 2017 was 614 tonnes in the Southern Gulf of Carpentaria, 32 tonnes in the Northern Gulf of Carpentaria, 81 tonnes in the North East Coast, 55 tonnes in the Mackay, and 47 tonnes in the Central East Coast. To assess the status of each barramundi stock, an age-structured population model with an annual time step was applied. The model data inputs included annual barramundi harvests, catch rates, age frequencies and life history characteristics. The current stock assessment updates previous assessments by considering an age-structured model rather than a simple surplus model (as per Campbell 2007) for the five main genetic barramundi stocks. It also incorporates changes in legal size limits as well as a scenario analysis considering the effects of recreational harvest. The model uses commercial catch data from 1988 to 2017 on the East Coast of Queensland and from 1989 to 2017 in the Gulf of Carpentaria. For scenario analyses, recreational survey data were used. For all but the Northern Gulf stock, length-and-age frequency data, collected by Fishery Monitoring (Fisheries Queensland) from commercial samples from 2000 to 2017 were incorporated in the model. The assessment provides estimates of exploitable biomass in 2017 relative to 1988-89 levels and recommends Total Allowable Commercial Catches for five of the seven stocks