Mother-embryo isotope fractionation in the pygmy devilray Mobula kuhlii cf. eregoodootenkee.

We determined stable-isotope ratios for replicate muscle tissues in 13 gravid Mobula kuhlii cf. eregoodootenkee (110.4-120.

Reducing the marine debris of recreational hoop nets in south-eastern Australia.

Alternative configurations of Australian recreational portunid hoop nets were investigated to address debris and selectivity issues. Four treatment nets (all comprising 152-mm polyamide-PA mesh) were assessed that differed in their twine (conventional multifilament vs new multi-monofilament) and fishing configuration (conventional conical vs inverted shapes). The conical multifilament design lost means (±SEs) of 130.

Effects of Modified Handling on the Physiological Stress of Trawled-and-Discarded Yellowfin Bream (Acanthopagrus australis).

Modified handling is often claimed to reduce (sub-)lethal impacts among organisms caught-and-released in fisheries. Improving welfare of discarded fish warrants investigation, when their survival is of both economic and ecological importance. In this study, juvenile yellowfin bream (Acanthopagrus australis) were trawled in an Australian penaeid fishery and then discarded after on-board sorting in either dry or water-filled (modified) trays and with delays in starting sorting of either 2 or 15 mins.

A 'simple anterior fish excluder' (SAFE) for mitigating penaeid-trawl bycatch.

Various plastic strips and sheets (termed 'simple anterior fish excluders'-SAFEs) were positioned across the openings of penaeid trawls in attempts at reducing the unwanted bycatches of small teleosts. Initially, three SAFEs (a single wire without, and with small and large plastic panels) were compared against a control (no SAFE) on paired beam trawls. All SAFEs maintained targeted Metapenaeus macleayi catches, while the largest plastic SAFE significantly reduced total bycatch by 51% and the numbers of Pomatomus saltatrix, Mugil cephalus and Herklotsichthys castelnaui by up to 58%.

Angling-induced barotrauma in snapper Chrysophrys auratus: are there consequences for reproduction?

In response to concerns regarding the potential for sub-lethal impacts of barotrauma on reproductively active Chrysophrys auratus during catch and release, 90 males and 90 females representing five reproductive stages (immature or resting--28%, developing--8%, developed--7%, ripe or spawning--23% and spent--34%) were angled from 8-70 m and macroscopically assessed (on-board and then in a laboratory). Irrespective of sex, all fish exhibited various clinical signs of barotrauma, including a prolapsed cloaca (60% of fish); gastric herniation (46%); ruptured swim bladder (73%); organ displacement (48%); and kidney (3%), liver (73%) and coloemic-cavity haemorrhaging (33%); with the frequency of nearly all positively associated with capture depth. Reproductive stage was also an important barotrauma predictor (reflecting related morphological changes) with a general trend towards spent fish least likely to incur the various clinical signs--especially for a prolapsed cloaca (also common among immature or resting fish and significantly affected by food in the digestive tract) and a ruptured swim bladder (common among ripe or spawning fish).

Configuring the mesh size, side taper and wing depth of penaeid trawls to reduce environmental impacts.

The effects of reducing mesh size while concomitantly varying the side taper and wing depth of a generic penaeid-trawl body were investigated to improve engineering performance and minimize bycatch. Five trawl bodies (with the same codends) were tested across various environmental (e.g.

Ocean acidification and fertilization in the antarctic sea urchin Sterechinus neumayeri: the importance of polyspermy.

Ocean acidification (OA), the reduction of the seawater pH as a result of increasing levels of atmospheric CO2, is an important climate change stressor in the Southern Ocean and Antarctic. We examined the impact of OA on fertilization success in the Antarctic sea urchin Sterechinus neumayeri using pH treatment conditions reflective of the current and near-future "pH seascape" for this species: current (control: pH 8.052, 384.

Beta diversity of demersal fish assemblages in the North-Eastern Pacific: interactions of latitude and depth.

Knowledge of broad-scale global patterns in beta diversity (i.e., variation or turnover in identities of species) for marine systems is in its infancy.

Incorporating the intraspecific occupancy-abundance relationship into zero-inflated models.

Zero-inflated versions of standard distributions for count data are often required in order to account for excess zeros when modeling the abundance of organisms. Such distributions typically have as parameters lambda, the mean of the count distribution, and pi, the probability of an excess zero. Implementations of zero-inflated models in ecology typically model lambda using a set of predictor variables, and pi is fit either as a constant or with its own separate model.

Much ado about nothings: using zero similarity points in distance-decay curves.

Distance decay is used to describe the (usually exponential) decay in ecological similarity of assemblages between two sites as a function of their distance apart along an environmental gradient. Exponential distance-decay curves are routinely fitted by calculating the ecological similarity between each pair of sites, and fitting a linear regression to the points on a scatter plot of log-similarity vs. distance (x-axis).

Mitigating discard mortality from dusky flathead Platycephalus fuscus gillnets.

The mortalities and contributing parameters were estimated for key species discarded during commercial gillnetting (80 mm mesh) targeting dusky flathead Platycephalus fuscus in a southeastern Australian estuary. Bycatches (1470 individuals from 16 species over 11 deployments) were assessed for their immediate mortalities onboard the gillnetter, before subsamples (570 individuals from 11 species) were discarded into cages and monitored for their short-term fate over 4 d. Appropriate controls were concurrently caged and monitored.

Comparison of hierarchical Bayesian models for overdispersed count data using DIC and Bayes' factors.

When replicate count data are overdispersed, it is common practice to incorporate this extra-Poisson variability by including latent parameters at the observation level. For example, the negative binomial and Poisson-lognormal (PLN) models are obtained by using gamma and lognormal latent parameters, respectively. Several recent publications have employed the deviance information criterion (DIC) to choose between these two models, with the deviance defined using the Poisson likelihood that is obtained from conditioning on these latent parameters.

Mortality of discards from southeastern Australian beach seines and gillnets.

Two experiments were done in an Australian estuary to quantify the mortalities and contributing factors for key species discarded during 8 and 9 deployments of commercial beach (or shore) seines and gillnets, respectively. In both experiments, bycatches (2347 individuals comprising 16 species) were handled according to conventional practices and assessed for immediate mortalities before live samples of selected species were discarded into replicate cages along with appropriate controls, and monitored for short-term mortalities (< or =10 d). All of the seined or gilled fish were alive prior to discarding.

Nonlinear multivariate models of successional change in community structure using the von Bertalanffy curve.

von Bertalanffy curves were used to describe the nonlinear relationship between assemblages inhabiting holdfasts of the kelp Ecklonia radiata and the volume of the holdfast. This was done using nonlinear canonical analyses of principal coordinates (NCAP). The volume of the holdfast is a proxy for the age of the plant and, thus, the canonical axis is a proxy for succession in the marine invertebrate community inhabiting the holdfast.

Sensitivity of Bayes estimators to hyper-parameters with an application to maximum yield from fisheries.

Priors are seldom unequivocal and an important component of Bayesian modeling is assessment of the sensitivity of the posterior to the specified prior distribution. This is especially true in fisheries science where the Bayesian approach has been promoted as a rigorous method for including existing information from previous surveys and from related stocks or species. These informative priors may be highly contested by various interest groups.

The kinetics of monospermic and polyspermic fertilization in free-spawning marine invertebrates.

The equation of Vogel et al. (1982) is widely used in fertilization studies of free-spawning marine invertebrates to predict the percentage of viable eggs that will be fertilized at any specified levels of gamete concentration and contact time. Here, the random collision model that underlies the Vogel et al.