Fishing Research Articles

Spatial variation in propagule pressure and establishment of zebra mussels (Dreissena polymorpha) within a subtropical reservoir

This work was funded in part by grants from the Oklahoma Department of Wildlife Conservation, through the Sport Fish Restoration Program, Grant F-61-R, and the National Science Foundation (Grant numbers NSF-IOS 1712936 and NSF DEB 1831061) to KDH, the University of Oklahoma Biological Station (through Graduate Research Fellowships to TCH and JEB) and the University of Oklahoma Department of Biology (through Adams Fellowships to TCH and JEB), the Graduate Student Senate at the University of Oklahoma (through a research grant to TCH), and by Sigma Xi through a grant in aid of research to TCH. Open Access fees paid for in whole or in part by the University of Oklahoma Libraries.

Short term temperature fluctuations affect embryonic and larval development of yellow perch (Perca flavescens)

Early life stages of fishes are critical stages due to their importance in enhancing recruitment. Given the high mortality through the embryonic and larval stages, managers have started investigating factors that impact these stages. Environmental factors, such as water temperature, have been found to play a larger role in early life survival. Climate change predications will be more apparent in northern temperate systems like the Great Lakes. Yellow perch Perca flavescens are an important sport fish in the region whose populations have been declining since the 1980s. Yellow perch recruitment is highly erratic due to the species dependence on spring water temperatures. With warming waters occurring earlier in the seasons, it is unsure how wild yellow perch will adapt. The objective of this study was to determine how variations in temperature regimes during the egg incubation period would impact embryonic and larval development in yellow perch. Four different temperature treatments were used in this study: steady temperature at 16°C, a gradient starting at 12°C increasing by 1-2°C every 3-4 days, a heat shock on day six of 20°C for 16 hours to mimic a heat wave event, and finally, a cold shock on day six of 10°C temperatures for 16 hours to mimic a cold snap event. The results of this study confirm that water temperatures severely impact embryonic development and incubation periods of yellow perch, having a significant impact on the percent of failed larvae at the end of the incubation period (P= 0.0005), with the cold shock affecting the lowest percent of failed larvae (0.8%) while the steady treatment had the highest percent (22.9%). Temperature treatment did have a significant impact on the time it took for larvae to successfully hatch out (P<0.001), but no significant effect on observed mortality and estimated mortality (P= 0.96), percent of surviving larvae (P=0.35), or average growth rate of larvae (P=0.16).This study reveals that yellow perch are better adapted to withstand acute cold shifts in water temperature than acute warming events. Climate change could potentially hinder an already struggling Lake Michigan yellow perch population.

DIVERSIDADE DE PEIXES NA ZONA COSTEIRA DO ESTADO DO MARANHÃO A PARTIR DE DADOS DA PESCA ESPORTIVA

The state of Maranhão has a vast coastline that promotes the development of coastal recreational fishery, an activity that has attracted more and more fans in recent years. In this context, the objective of this work was to demonstrate the importance of sport fishing as an auxiliary source in monitoring the diversity of fish on the beaches of the metropolitan region of São Luís, Maranhão, through the monitoring of sport fishing tournaments, held in December 2018 on the beach do Olho d‟água and in July 2019, at Araçagi beach. The captured fish were stored in isothermal boxes containing ice and transported to the laboratory for taxonomic identification. 252 specimens were captured, belonging to 19 species, and distributed in 10 families. The family Sciaenidae was the most representative with 3 species. The predominant species were Conodon nobilis and Genyatremus luteus from the Haemulidae family, which together represented 39% of the specimens captured on the Olho d‟água beach and 24% on the Araçagi beach. The individuals of C. nobilis had an average weight of 29.4 ± 12.7 g and an average length of 12.3 ± 2.0 cm, with a curve of weight x length ratio represented by the equation PT = 0.034 CT2.6637 and R2 = 0, 67, with b = 2.67. While in G. luteus, the individuals had an average weight of 96.5 ± 82.2 g and an average length of 15.8 ± 4.4 cm, with a curve of the weight x length ratio represented by the equation: PT = 0.0145CT3.0999 and R2 = 0.81, with b = 3.09. The diversity of fish in beach fisheries can contribute to studies of fishery biology to support the development of management strategies and conservation of fish stocks.

A Study on Characteristics of Fuel Consumption of Fishing Fleet Depending on Domestic Littoral Sea Fisheries Catches-Focusing on Mackerel Fishing of Large Purse Seines-

A Study on Characteristics of Fuel Consumption of Fishing Fleet Depending on Domestic Littoral Sea Fisheries Catches-Focusing on Mackerel Fishing of Large Purse Seines-

Maximum Length Report of Gonostoma denudatum Rafinesque, 1810 in the Eastern Mediterranean Sea

The present paper reports the maximum length of the rare seen deep-sea fish bristlemouth Gonostoma denudatum Rafinesque, 1810 in the Mediterranean. One specimen of G. denudatum was caught using a trawler from the deep seas of Northern Cyprus waters on June 22th 2019. The total length (TL) of the specimen was 165 mm, the standard length (SL) was 149.5 mm, and the total weight was 16.2 g. Till today, this sample shown to this species maximum length (TL), which was recorded for the Mediterranean as well as in Eastern basin waters.

Contação e Cantação de Histórias: A Formação dos Sujeitos e a Manutenção das Práticas Culturais da Vila De Regência Augusta

Regência Augusta faz parte do município de Linhares. Trata-se de um pequeno vilarejo rodeado pela foz do Rio Doce e o mar. Em maior parte, a comunidade é descendente da miscigenação entre indígenas, negros e brancos, comumente chamados na região de nativo ou caboclo. Estes sujeitos estão intimamente ligados a duas práticas culturais locais: a pescaria e o Congo. Nesse estudo, alguns apontamentos se mostraram expressivos: a memória coletiva e a transmissão dos saberes tradicionais, o trabalho da pescaria como prática cultural local e a proximidade entre a pesca e o congo. Os testemunhos aparecem nas ações de contação e cantação das histórias, influenciando e mobilizando a formação dos sujeitos. As identificações trazidas nas narrativas, tanto da Pesca como do Congo, demonstraram que as práticas contribuem para formação da vida prática, nos aspectos culturais e sociais da vila.

Pengaruh Suhu daPengaruh Suhu dan Kedalaman Terhadap Hasil Tangkapan Yellowfin Tuna di Perairan Samudera Indonesia Selatan Pulau Jawa n Kedalaman Terhadap Hasil Tangkapan Tuna Long Line di Perairan Samudera Indonesia, Selatan Pulau Jawa

Penelitian ini dilaksanakan di PPS. Cilacap dengan daerah penangkapan Samudera Indonesia pada bulan Maret sampai dengan Mei 2020 yang bertujuan untuk menmgetahui pengaruh suhu air laut dan kedlaman pancing terhadap hasil tangkapan yellowfin tuna. Pengumpulan data primer dilakukan dengan pengamatan langsung mengikuti operasi penangkapan long line selama 1 (satu) trip dengan KM. Trans Bahari 3, meliputi data waktu setting dan hauling, panjang main line, jumlah pancing, hasil tangkapan, daerah penangkapan (fishing ground), serta data suhu dan kedalaman perairan. Sedangkan pengumpulan data sekunder dilakukan melalui wawancara dan data Pelabuhan Perikanan Samudera Cilacap. Analisa data dilakukan dengan menghitung nilai hook rate, kedalaman mata pancing, serta pengaruh suhu dan kedalaman pancing terhadap hasil tangkapan yellowfin tuna melalui metode uji t. Dari hasil Analisa data diperoleh nilai total hook rate sebesar 1,33, kedalaman mata pancing berada antara 90,2 m – 181,4 m, dengan kisaran suhu vertikal antara 12,5⁰ C – 25,0⁰ C. Pengaruh suhu dan kedalaman terhadap hasil tangkapan yellow tuna berpengaruh nyata (significant) antara kedalaman A dengan C, sedangkan antara kedalaman A dengan B, dan kedalaman B dengan C masing-masing tidak memberikan perbedaan yang nyata (non significant).

More Than Expected From Old Sponge Samples: A Natural Sampler DNA Metabarcoding Assessment of Marine Fish Diversity in Nha Trang Bay (Vietnam)

Sponges have recently been proposed as ideal candidates to act as natural samplers for environmental DNA due to their efficiency in filtering water. However, validation of the usefulness of DNA recovered from sponges to reveal vertebrate biodiversity patterns in Marine Protected Areas is still needed. Additionally, nothing is known about how different sponge species and morphologies influence the capture of environmental DNA and whether biodiversity patterns obtained from sponges are best described by quantitative or qualitative measures. In this study, we amplified and sequenced a vertebrate specific 12S barcode with a set of universal PCR primers (MiFish) for metabarcoding environmental DNA from fishes, to unveil fine-scale patterns of fish communities from natural-sampler DNA retrieved from 64 sponges (16 species) located in eutrophic and well-preserved coral reefs in Nha Trang Bay (central Vietnam). Ninety tropical fish species were identified from the sponges, corresponding to one third of the total local ichthyofauna reported from previous extensive conventional surveys. Significant differentiation in fish communities between eutrophic and well-preserved environments was observed, albeit eutrophication only explained a modest proportion of the variation between fish communities. Differences in efficiency of capturing fish environmental DNA among sponge species or morphologies were not observed. Overall, the majority of detected fish species corresponded to reef-associated small-sized species, as expected in coral reefs environments. Remarkably, pelagic, migratory, and deep-sea fish species were also recovered from sponge tissues, pointing out the ability of sponge natural sampled DNA to detect fishes that were not permanently associated to the biomes where the sponges were sampled. These results highlight the suitability of natural samplers as a cost-effective way to assess vertebrate diversity in hyper-diverse environments.

Ultra-Black Deep-Sea Fishes

This year, our research group reported that a simple pigment-packing mechanism has likely evolved multiple times to produce ultra-black skin in deep-sea fishes, and showed, using finite-difference time-domain modeling, that the melanosomes in ultra-black fishes are optimized in size and shape to minimize reflectance. The work has implications for the creation of robust, easy-to-manufacture ultra-black materials.

Perceived Ecological Threats and Economic Benefits of Non‐Native Black Bass in the United States

Black bass Micropterus spp. are highly sought‐after sport fish and, where introduced, are emblematic of the tradeoffs between ensuring productive fisheries and conserving native biodiversity. To disentangle these potentially conflicting interests, we administered a survey of fisheries biologists in the United States to assess perceptions regarding ecological and economic impacts of non‐native black bass between anthropogenic and natural habitats. Our results indicate that non‐native black bass are generally considered economically beneficial in both habitat types. Contrastingly, these species were perceived to have significantly more negative ecological impacts in natural than anthropogenic habitats. Our findings suggest that habitat may be an important factor to partition the conflicting ecological–economic dynamic of non‐native black bass. Implications of this study suggest that challenges remain for managers attempting to balance the paradoxical nature of these species as both desired sport fishes and as potentially harmful invaders when found outside their native range.

Review of life history parameters and preliminary age estimates of some New Zealand deep-sea fishes

ABSTRACT A literature review on longevity of New Zealand deep-sea fishes provided life history parameter estimates for 17 bony and five cartilaginous species. Preliminary age estimates for a further nine deep-sea bony fishes were made from otolith zone counts and included results from a pilot analysis of radiocarbon age estimates from the otoliths of three of the species. Radiocarbon age estimates corroborated the otolith zone count age estimates made for white rattail (Trachyrincus aphyodes) and smallhead cod (Lepidion microcephalus) but were substantially lower for the third species, smallscale brown slickhead (Alepocephalus antipodianus) which suggested that it was not exposed to elevated (near-surface) levels of 14C in early life. Validation of otolith zone age estimates is difficult for deep-sea species but the radiocarbon analysis provided a practical method to corroborate age estimates for some bony fishes. Of the 31 fish in this study (known and new age estimates), five of the fishery target species and 10 of the bycatch were long-lived (50 years or more). The hypothesis that all New Zealand deep-sea species are long-lived was not supported, but the chance of a species being long-lived seem to be higher in deeper water.

Micro- and Ultramicroelemental Content in Otoliths of Blue Antimora Antimora rostrata and Pacific Flatnose A. microlepis (Moridae, Teleostei)

The content of 53 micro- and ultramicroelements in otoliths of two deep-sea fish species, blue antimora Antimora rostrata from the Northwest Atlantic (NWA) and Pacific flatnose Antimora microlepis from the Northeast Pacific (NEP), is studied. The otoliths of these species were characterized by the maximum concentration of strontium, nickel, zinc, barium, chromium, copper, lithium, cobalt, and zirconium (in descending order). The content of barium, tungsten, and lithium was higher in otoliths of the former species, while that of yttrium and uranium, in otoliths of the latter. This is probably due to differences in the chemical composition of NWA and NEP waters, as well as to differences in the linear size of fishes and changes in the concentrations of individual elements during ontogeny. The lead, arsenic, zinc, copper, and nickel contents in the otoliths, kidneys, muscles, and liver of fishes from different areas are compared.

Overexploitation and More Than a Decade of Failed Management Leads to No Recovery of the Galápagos Sea Cucumber Fishery

Isostichopus fuscus is the most important sea cucumber species exploited in the Eastern Tropical Pacific. It was the most important fishery in the Galapagos in the early 2000s until overfishing led to its collapse and a 5-year total fishing ban was established (2016 to 2021) to try to recover it. The management of I. fuscus in the Galapagos has always considered the population density as an indicator for decision-making. The objective of this study is to review the density as an indicator of the population status of I. fuscus using a stock-production model incorporating covariates methodology. For the first time, population and fishing parameters (K, r and q), reference points (MSY, BMSY, FMSY and DMSY) and indicators (B/BMSY and F/FMSY) were estimated for I. fuscus. The results indicate that the management measures have not prevented the overexploitation of this species for more than a decade. The goal of the I. fuscus management plan in the Galapagos, i.e. the recovering the fishery in a non-fishing scenario, will not be met by 2030. To accomplish its recovery six recommendations are proposed, including to extend the total ban of the fishery and to change the current management indicators to B/BMSY and F/FMSY. This study evidences that management measures taken with little scientific basis can have a pervasive effect on natural resources.

Leveraging integrated spatial planning for sustainable regulation of coastal tourism activities in Malindi town, Kenya

Unprecedented demand for both land and ocean space within the coastal zone to support tourism has continued to negatively impact the coastal marine environment leading to degradation. Poorly planned and regulated tourism activities on land and sea have led to degradation of environmentally sensitive marine areas, encroachment on public beaches, erosion of the shoreline and blockage of public access points to the beaches. These impacts transcend the land and ocean continuum necessitating the need for regulation. Spatial planning is one of the key tools that provides a pre-emptive strategic framework for regulating tourism uses so as to prevent harmful development and mitigate the impact of potentially polluting activities. However, spatial planning as applied in Kenya has focused on the regulation of physical developments on land such as the construction of hotels but not on the related tourism activities that emanate from such developments. In this case, activities that tourists engage in outside of the physical hotel structure such as swimming, leisure walks, sport fishing, souvenir collection, and snorkeling are not the subject of spatial planning leading to unsustainable use within the coastal zone. This study makes a case for adopting an integrated spatial planning approach as a lever for regulating tourism activities within this expanded lens, beyond just the buildings and activities that take place within the hotel establishments. The spatial planning approach would include a holistic regulation of coastal tourism activities within both terrestrial and marine spaces in order to attain sustainable management of the marine ecosystem.

Retraction Note: Novel life history strategy in a deep sea fish challenges assumptions about reproduction in extreme environments

Editor's Note: this Article has been retracted; the Retraction Note is available at https://doi.org/10.1038/s41598-020-75408-8

Evidence Dorsal Spine Removal is Nonlethal and Unharmful for Largemouth Bass in Florida

AbstractLargemouth Bass Micropterus salmoides, Florida Bass Micropterus floridanus, and their intergrade are socially and economically valuable sport fish. In the southeastern United States, it is customary for fisheries personnel to age black bass Micropterus species using sagittal otoliths, which requires killing the fish. Presently, fisheries managers and black bass anglers show reluctance to sacrifice large individuals. Development of a nonlethal ageing technique would not only allay concerns of sacrificing large black bass, but it could offer a pathway for new research, management, and conservation. We excised dorsal spines III–V from Largemouth Bass in Florida varying from 30 to 57 cm total length to evaluate the effects of the procedure on survival over 35 d. No mortalities were observed for fish with excised dorsal spines, and experiment-wide survival was 0.94 (0.87–1.00; 95% confidence interval). No significant differences in survival, weight change, or incidence of external injuries were observed between control and excised fish. The areas of spine excision healed with no visible infection or inflammation at the conclusion of the experiment. Therefore, dorsal spine removal offers managers a nonlethal option for collecting ageing structures of adult Largemouth Bass in Florida, including large individuals, and this result likely extends to other Micropterus species as well.

Nestling Diet and Breeding Success of Little Bitterns Ixobrychus minutus at Two Artificial Fishpond Complexes in South-Western Slovakia

Artificial fishponds are assumed to be suitable alternative habitat for many waterbirds including fish-eating predators such as herons. However, fish farming may lead to contrasting consequences for birds breeding in these biotopes and act as an ecological trap. I examined nestling diet and reproductive success of the least studied heron species in Europe, the endangered Little Bittern Ixobrychus minutus, at two fishpond complexes in south-western Slovakia. A total of 95 breeding attempts by this species were recorded during 2015–2019 in the study area, 84% of which produced at least one nestling. Despite relatively high nest success at both sites, the number of fledged nestlings differed significantly between the two fishpond complexes. The observed differences were mainly caused by higher nest predation at one of the fishponds. The diet of nestlings also differed between study sites. While the food taken at fishponds that are used for intensive farming of Common Carp Cyprinus carpio contained significant proportions of insects (41%) and amphibians (14%), at fishponds used mainly for individual sport fishing, parents fed their nestlings exclusively fish. However, the total amount of food delivered to nestlings was similar at both fishpond complexes. This suggests that Little Bitterns are able to adapt to fishponds with various intensities of management. Nevertheless, considering differences in nest predation risk between studied fishponds, other factors such as abundance and structure of littoral vegetation and predator abundance, can influence the breeding success of this species in artificial fishpond habitats. Identifying such factors may be important for the conservation and management of this species.

Correspondence between a recreational fishery index and ecological condition for U.S.A. streams and rivers

Sport fishing is an important recreational and economic activity, especially in Australia, Europe and North America, and the condition of sport fish populations is a key ecological indicator of water body condition for millions of anglers and the public. Despite its importance as an ecological indicator representing the status of sport fish populations, an index for measuring this ecosystem service has not been quantified by analyzing actual fish taxa, size and abundance data across the U.S.A. Therefore, we used game fish data collected from 1,561 stream and river sites located throughout the conterminous U.S.A. combined with specific fish species and size dollar weights to calculate site-specific recreational fishery index (RFI) scores. We then regressed those scores against 38 potential site-specific environmental predictor variables, as well as site-specific fish assemblage condition (multimetric index; MMI) scores based on entire fish assemblages, to determine the factors most associated with the RFI scores. We found weak correlations between RFI and MMI scores and weak to moderate correlations with environmental variables, which varied in importance with each of 9 ecoregions. We conclude that the RFI is a useful indicator of a stream ecosystem service, which should be of greater interest to the U.S.A. public and traditional fishery management agencies than are MMIs, which tend to be more useful for ecologists, environmentalists and environmental quality agencies.

Yearling Muskellunge Poststocking Behavior and Survival in Two Central Iowa Reservoirs with Contrasting Habitat Availability

AbstractMuskellunge Esox masquinongy is a prized sport fish throughout much of North America. Due to the species’ popularity among anglers and limited natural recruitment in reservoirs, Muskellunge are commonly stocked to maintain populations. However, little is known about their poststocking behavior and survival in reservoirs. We used radiotelemetry to evaluate behavior and survival of spring‐stocked yearling Muskellunge in two Iowa reservoirs that differed in habitat availability (Big Creek Lake: limited habitat; Brushy Creek Lake: abundant habitat). Hatchery‐reared Muskellunge were implanted with radio transmitters (n = 15–16 fish·lake−1·year−1; 61 fish total) and stocked in both lakes during May 2017 and 2018; fish were tracked daily for 1 week, every other day for the second week, and then weekly until December. Telemetry data were used to evaluate depth and vegetation use, selection of littoral substrate and coarse woody habitat (CWH) complexities, movement, home ranges, and survival. Muskellunge depth use generally increased with time poststocking and was greater in Brushy Creek Lake than in Big Creek Lake. Movement rates were greatest during the first week poststocking and declined thereafter, with greater rates and home ranges in Big Creek Lake. Muskellunge in both systems selected for fine substrates while avoiding coarse substrates. Muskellunge in Brushy Creek Lake were more commonly associated with CWH and aquatic vegetation compared to those in Big Creek Lake. Muskellunge in Big Creek Lake selected for complex CWH, while those in Brushy Creek Lake used CWH classes in proportion to their availability. Cormack–Jolly–Seber daily apparent survival estimates were lowest for the first 4 d poststocking and ranged from 0.59 to 0.99, after which survival increased from May to September before declining in October and November. Results of this study provide a greater understanding of the poststocking success of yearling Muskellunge and suggest that Muskellunge behavior and survival are dependent on habitat complexity, with weaker habitat selection but higher survival in complex systems.

Determination of acute median lethal concentration and sublethal effects on AChE activity of Gymnotus carapo (Teleostei: Gymnotidae) exposed to trichlorfon

Trichlorfon (TRF) is a pesticide widely used in aquaculture to control fish ectoparasites. This pesticide is an inhibitor of acetylcholinesterase, an essential enzyme for termination of nerve impulses. High rates of TRF use generate risks to the environment and human health. In the environment, pesticides can affect the local fauna and generate an ecological breakdown. There are several studies performed with fish production; however, gaps are created for native fish with other commercial values. The tuvira (Gymnotus carapo) is a fish native to Brazilian fauna and has great commercial importance in sport fishing. The present study aimed to determine the lethal concentration of trichlorfon (Masoten) in Gymnotus carapo and its sublethal effects on the enzyme AChE. In this study, the acute toxicity (the concentrations to kill 50% of the fish LC50) of TRF in tuviras (Gymnotus carapo) and acetylcholinesterase inhibition in liver and muscle tissue of tuviras submitted to sublethal concentrations were evaluated. For the acute assay, concentrations of 0.0, 5.0, 7.5, 15, 22.5, 30, 37.5 and 45 mg L-1 were used for a period of 96 h. After the acute exposure period, a LC50 of 6.38 mg L-1 was determined. In the sublethal assay, concentrations of 0.0, 0.238, 0.438 and 0.638 mg L-1 were used, based on 10% of the LC50, over a period of 14 days. Two collections were performed: one at seven days and the other at the end (day 14). Inhibition of acetylcholinesterase in the liver was only shown (p < 0.05) for the treatment with 0.638 mg L-1 after 14 days of exposure. At seven days, muscle activity showed a significant difference only for the treatments 0.438 and 0.638 mg L-1, compared with the treatment 0.238 mg L-1 and control. At 14 days of exposure, only the treatment 0.638 mg L-1 showed significant differences in relation to the other groups, thus showing that enzyme recovery had occurred. The value found in the acute test allowed the conclusion that TRF presents moderately toxic characteristics to Gymnotus carapo. The toxicity parameter values calculated in the present study assisted in estimation of maximum allowable limits in bodies of water when combined with test data from other non-target organisms.