Spatial variability in condition of southern rock lobsters (Jasus edwardsii) at the start of the Tasmanian fishing season

This research was funded by the Australian Seafood Cooperative Research Centre and the Fisheries Research and Development Corporation (project number 2014/726) (http://www.seafoodcrc.com/) (http://frdc.com.au/Pages/home.aspx). The Australian Research Council's Industrial Transformation Research Program (project number IH120100032) is gratefully acknowledged for providing further financial support for two authors to present this work at the Crustacean Society and International Association of Astacology Mid-year Meeting, 19-23 July 2015 (http://www.arc.gov.au/industrial-transformation-research-programme).The southern rock lobster (Jasus edwardsii) industry in Australia favours red lobsters, which are usually caught in shallow waters, over paler (brindle) lobsters. This preference is driven partly by the Chinese market, where red is associated with luck and prosperity, and additionally, by the widely held perception within the industry that brindles have greater mortality rates during out of water transport than reds. Limited scientific evidence supports these industry observations; however, these studies did not evaluate the initial condition of lobsters. This study aimed first, to determine which variables better describe condition in J. edwardsii and second, to compare condition among lobsters in several sites around Tasmania at the typical time of high transport mortality. Male lobsters were collected from the South West, South East, East and North coast of Tasmania in late November/December 2014, which correspond to the start of the Tasmanian fishing season. A comprehensive condition assessment was applied by measuring tissue proximal composition, Brix index, Total Haemocyte Count, pH, haemocyanin and another 16 haemolymph parameters of interest. A useful framework to compare condition in J. edwardsii was established by first, using Brix index as a measure of nutritional condition, second, using pH, magnesium, and bicarbonate to evaluate differences in physiological condition and finally, using THC counts as a proxy for lobster health condition. Lobsters from different sites had different nutritional, physiological and health condition, consistent with industry observations, however our results indicate that some red shallow water lobsters exhibited poorer nutritional and health condition, while some deep water brindle lobsters were in good condition. Differences in condition could not be directly associated to catch depth of lobsters and was related to other spatially discrete factors which sometimes vary over distances <3 km.Publisher PDFPeer reviewe

Assessing bait use by static gear fishers of the Scottish Inshore fisheries : a preliminary study

Approximately 70 % of the Scottish fishing fleet target shellfish using baited creels. Bait is an essential component of catch success, but the economic and environmental implications of bait use are unknown. In this preliminary study, a short survey was circulated to members of the Scottish inshore creeling fleet and analysed alongside spatial data from 8 creel fishing vessels. Bait biomass, input into coastal waters through creeling activity, was calculated along with bait types, motivations surrounding the discarding of used bait and the annual estimated spatial concentration. Findings indicate that preferred bait types differ with geographic location and cost the creeling sector approximately £9.8 million annually at the time of the survey, equating to 16.3 % of the nominal 2018 shellfish landing value. Data from this research suggests that approximately 13,492 metric tonnes of bait biomass enters coastal Scottish waters through creeling activities annually. Vessel tracks showed fishers returning to certain fishing grounds repeatedly, indicating that bait biomass input is highly localised. Hotspots of fishing activity were calculated to receive up to 75 kg ha−1 and 47 kg ha−1 of bait biomass per fisher annually when fishing Nephrops and crab/ lobster, respectively. Bait discarding occurs most frequently at the fishing grounds with convenience being the main motivation. This study provides a baseline for future studies and prompts the consideration of bait use in the management of creel fisheries.PostprintPeer reviewe

Minimising discards while taking revenue into account : spatio-temporal assessment of catches in an artisanal shrimp trawl fishery in Peru

Funding: Newton Fund (414695818); University of St Andrews Impact and Innovation 2021; Fondo Nacional de Desarrollo Científico Tecno 2018-222.Around 4.2 million tonnes of fish and other species, some of which are of conservation concern, are discarded every year in bottom trawl fisheries. This study focusses on a small-scale shrimp trawl fishery located in northern Peru that operates with high level of discards which causes conflict with other local fishers. Despite trawling being an illegal activity within the 5NM off the coast, this fishery has been operating in these inshore areas for over 40 years because it sustains the well-being of hundreds of fishers. This study aimed to identify the factors that affect the spatio-temporal variation in catches in order to propose recommendations that can be adopted by fishers to minimise their impact on the ecosystem while still providing economic opportunities. The spatial distributions of shrimp, main commercial species and discards were modelled over time using hierarchical generalised additive models. Strong spatio-temporal variation was observed for all catch components and moon phase affected commercial species and discards differently. The results show that, to reduce the environmental impacts of this fishery in the short-term, the fishing area could be divided into north and south and that fishing activities should be limited to the southern area in the autumn. Other recommendations rely on temporal closures during the week of the first quarter of the moon phase. Finally, considering the institutional weaknesses in monitoring, control and surveillance, we suggest that the only realistic approach to reduce the fishery's environmental impacts in the short-term is to foster the willingness of fishers to adopt responsible fishing practices. Yet, long-term solutions will require comprehensive co-management efforts.Publisher PDFPeer reviewe

Estimating fishing effort in small-scale fisheries using high-resolution spatio-temporal tracking data (an implementation framework illustrated with case studies from Portugal)

Marta M. Rufino is funded by a DL57 contract (junior researcher) awarded by IPMA within the project “Real-time monitoring of bivalve dredge fisheries” (MONTEREAL, MAR-01.03.02-FEAMP-0022), funded by the Fisheries Operational Programme (MAR 2020) and co-financed by the European Maritime and Fisheries Fund (EMFF 2014–2020). João Samarão received a research grant (Ref: IPMA-2022-015-BII) awarded by IPMA within the framework of the project PESCAPANHA.Small-scale fisheries (SSF, boats < 12 m) represent 90% of this sector at a worldwide scale and 84% of the EU fleet. Mapping the areas and intensity where the fishing operations occur is essential for spatial planning, safety, fisheries sustainability and biodiversity conservation. The EU is currently regulating position tracking of SSF fishing vessels requiring precision resolved geo-positional data (sec to min resolution). Here we developed a series of procedures aimed at categorizing fishing boats behaviour using high resolution data. Our integrated approach involve novel routines aimed at (i) produce an expert validated data set, (ii) pre-processing of positional data, (iii) establishing minimal required temporal resolution, and (iv) final assessment of an optimized classification model. Objective (iv) was implemented by using statistical and machine learning (ML) routines, using novel combinations of fixed thresholds estimates using regression trees and classification methods based on anti-mode, Gaussian Mixture Models (GMM), Expectation Maximisation (EM) algorithms, Hidden Markov Models (HMM) and Random Forest (RF). Of relevance, the final evaluation framework incorporates both error quantification and fishing effort indicators. We tested the method by running through four SSF fisheries from Portugal recorded every 30 sec, with 183 boat trips validated, and concluded that the more robust time interval for data acquisition in these metiers should bePublisher PDFPeer reviewe

Habitat characteristics predicting distribution and abundance patterns of scallops in D'Entrecasteaux Channel, Tasmania

This project was funded by the Fishwise Community Grants Scheme administered by the Department of Primary Industries, Parks, Water and Environment, Australia. The first author was supported by an Endeavour International Postgraduate Research Scholarship (EIPRS).Habitat characteristics greatly influence the patterns of distribution and abundance in scallops, providing structure for the settlement of spat and influencing predation risk and rates of survival. Establishing scallop-habitat relationships is relevant to understanding the ecological processes that regulate scallop populations and to managing critical habitats. This information is particularly relevant for the D'Entrecasteaux Channel, south-eastern Tasmania (147.335 W, 43.220 S), a region that has supported significant but highly variable scallop production over many years, including protracted periods of stock collapse. Three species of scallops are present in the region; the commercial scallop Pecten fumatus, the queen scallop Equichlamys bifrons, and the doughboy scallop Mimachlamys asperrima . We used dive surveys and Generalized Additive Modelling to examine the relationship between the distribution and abundance patterns of each species and associated habitat characteristics. The aggregated distribution of each species could be predicted as a function of sediment type and species-specific habitat structural components. While P. fumatus was strongly associated with finer sediments and E. bifrons with coarse grain sediments, M. asperrima had a less selective association, possibly related to its ability to attach on a wide range of substrates. Other habitat characteristics explaining P. fumatus abundance were depth, Asterias amurensis abundance, shell and macroalgae cover. Equichlamys bifrons was strongly associated with macroalgae and seagrass cover, whereas M. asperrima abundance was greatly explained by sponge cover. The models define a set of relationships from which plausible hypotheses can be developed. We propose that these relationships are mediated by predation pressure as well as the specific behavioural characteristics of each species. The findings also highlight the specific habitat characteristics that are relevant for spatial management and habitat restoration plans.Publisher PDFPeer reviewe

Bycatch and discards in the artisanal shrimp trawl fishery in Northern Peru

Funding: Mark James and Tania Mendo appreciate the financial support of the Newton-Paulet Fund (IL 2018-Grant Agreement 414695818 James PER) and Jaime Mendo from the National Fund for Scientific and Technological Development (FONDECYT 2018-222).This study analyses the bycatch composition of an artisanal shrimp trawl fleet operating between Cabo Blanco and Máncora in Northern Peru between April 2019 and March 2020. A total of 300 hauls were analysed with respect to target catch and bycatch (consisting of other commercial species, discards, and macroalgae). A total of 277 species were recorded including 111 species of fish, 65 species of molluscs, 51 species of crustaceans, 22 species of algae, 12 species of cnidarian, 9 species of echinoderms, 4 species of Bryozoa and 3 species of polychaeta. Capture per unit effort (CPUE, kg.h-1) was highest for fish, followed by crustaceans, algae and molluscs. The target species Penaeus californiensis coffee shrimp constituted 17.8% of the overall catch,82.2% represented bycatch, and 50.6% represented discards. Coffee shrimps were more abundant in June and November 2019 and in January and February 2020. Highest bycatch CPUE occurred in May, June and December 2019. The most abundant species in the bycatch throughout the study period were sand perch (Diplectrum conceptione, 16% weight of the total catch), the macroalgae caulerpa (Caulerpa filiformis, 13%), sole flounder (Etropus ectenes, 6.4%), Pacific drum (Larimus pacificus, 5.7%), and lumptail searobin (Prionotus stephanophrys, 5.1%). Overall, the contribution of sand perch and flounder, exceeded the weight of coffee shrimp, therefore the interpretation that shrimp is the sole target species needs to be revised. The number of discarded species per month increased towards the spring months with the highest value in November. This study represents the first characterisation of bycatch in the artisanal trawling fishery in the Piura region in northern Peru and reveals a high proportion of bycatch in the fishery but also hints at potential temporal management measures that could be imposed to reduce the levels of bycatch. For example, the months of May and December had the greatest bycatch to shrimp ratios and the fishery could potentially be closed to avoid high bycatch risk, however, longer term information is needed to assess if the trends observed in bycatch are similar over longer periods of time. The species characterisation of bycatch also provides information for the design of modified nets which would target the reduction of small fish present in the catch.Publisher PDFPeer reviewe

Identifying fishing grounds from vessel tracks: model-based inference for small scale fisheries

This study (T.M., M.J. and S.S.) was funded by the European Maritime Fisheries Fund ‘Scottish Inshore Fisheries Integrated Data System' (grant reference no. SCO1434). T.P. was supported by a Newton International Fellowship, funded by the Royal Society (grant reference no. NF170682).Recent technological developments facilitate the collection of location data from fishing vessels at an increasing rate. The development of low-cost electronic systems allows tracking of small-scale fishing vessels, a sector of fishing fleets typically characterized by many, relatively small vessels. The imminent production of large spatial datasets for this previously data-poor sector creates a challenge in terms of data analysis. Several methods have been used to infer the spatial distribution of fishing activities from positional data. Here, we compare five approaches using either vessel speed, or speed and turning angle, to infer fishing activity in the Scottish inshore fleet. We assess the performance of each approach using observational records of true vessel activity. Although results are similar across methods, a trip-based Gaussian mixture model provides the best overall performance and highest computational efficiency for our use-case, allowing accurate estimation of the spatial distribution of active fishing (97% of true area captured). When vessel movement data can be validated, we recommend assessing the performance of different methods. These results illustrate the feasibility of designing a monitoring system to efficiently generate information on fishing grounds, fishing intensity, or monitoring of compliance to regulations at a nationwide scale in near-real-time.Publisher PDFPeer reviewe

Factors affecting the spatial and temporal distribution of E. coli in intertidal estuarine sediments

Funding: University of St Andrews, The James Hutton Institute. DMP received funding from the Marine Alliance for Science and Technology for Scotland (MASTS), funded by the Scottish Funding Council (grant reference HR09011).Microbiological water quality monitoring of bathing waters does not account for faecal indicator organisms in sediments. Intertidal deposits are a significant reservoir of FIOs and this indicates there is a substantial risk to bathers through direct contact with the sediment, or through the resuspension of bacteria to the water column. Recent modelling efforts include sediment as a secondary source of contamination, however, little is known about the driving factors behind spatial and temporal variation in FIO abundance. E. coli abundance, in conjunction with a wide range of measured variables, was used to construct models to explain E. coli abundance in intertidal sediments in two Scottish estuaries. E. coli concentrations up to 6 log10 CFU 100 g dry wt-1 were observed, with optimal models accounting for E. coli variation up to an adjusted R2 of 0.66. Introducing more complex models resulted in overfitting of models, detrimentally effected the transferability of models between datasets. Salinity was the most important single variable, with season, pH, colloidal carbohydrates, organic content, bulk density and maximum air temperature also featuring in optimal models. Transfer of models, using only lower cost variables, between systems explained an average deviance of 42 %. This study demonstrates the potential for cost-effective sediment characteristic monitoring to contribute to FIO fate and transport modelling and consequently the risk assessment of bathing water safety.PostprintPeer reviewe

No experimental evidence of stress-induced hyperthermia in zebrafish (Danio rerio)

NJ was supported by a studentship from The Fisheries Society of The British Isles.Stress-induced hyperthermia (SIH) is characterised by a rise in body temperature in response to a stressor. In endotherms SIH is mediated by the autonomic nervous system, whereas ectotherms must raise their body temperature via behavioural means by moving to warmer areas within their environment (behavioural thermoregulation). A recent study suggested that zebrafish (Danio rerio), an important model species, may move to warmer water in response to handling and confinement and thus exhibit SIH, which, if accepted, may have important practical and welfare implications. However an alternative hypothesis proposed that the observed movements may been produced by avoidance behaviour rather than behavioural thermoregulation. Investigating the claims for SIH in zebrafish further we conducted two experiments that extend the earlier study. The first experiment incorporated new conditions that considered fish behaviour in the absence of thermal variation, i.e. their null distribution, an important condition that was not performed in the original study. The second was a refined version of the experiment to reduce the numbers of fish and aid movement between areas for the fish. In contrast to the previous study, we saw no effect of handling or confinement on preference for warmer areas, and no evidence for SIH in either experiment. Instead we observed a short-lived reduction in preference for warmer areas immediately post stress. Our work suggests that zebrafish may not experience SIH and claims regarding fish consciousness based on SIH may need to be revised.PostprintPeer reviewe

Challenging the tradition of a fishmeal producing countryan economic overview of the fishing activity of Piura, Peru

Piura is a region in northern Peru that stands out for its artisanal fisheries, export-oriented processing industry that focuses on products for direct human consumption (DHC), and marine gastronomy. We characterized the Piura region’s fisheries sector value chain for 2014 using primary and secondary information. This resulted in the estimation of indicators for production, value added (VA) and employment. Piura reported landings of 732,000 t of fish and invertebrates that generated U$D 1,771 million of income, U$D 700 million of VA and 49,000 jobs. The main supply chains of Piura’s landings were: (1) Industrial production and export of DHC products mainly sourced from artisanal fisheries (82% landings, 59% of AV, and 46% of employment), and (2) Supply of fresh seafood for domestic consumption (13% landings, 36% of AV, and 52% of employment). This region does not follow the national pattern for Peru. The latter is characterized by the massive industrial extraction of anchoveta for fishmeal and fish oil production (IHC). Finally, given that Peruvian artisanal fisheries have a long way to go before achieving sustainability, we discussed our findings within a broader governance framework seeking to strengthen participatory governance to prevent potential future collapses and increase the competitiveness of the economic activities characterized throughout this research.Publisher PDFPeer reviewe