Fish Distribution Research Articles

Diversity and distribution of goby-fry fish in Tomini Bay, Gorontalo, Indonesia

Diversity and distribution of goby-fry fish in Tomini Bay, Gorontalo, Indonesia

Behavioral characteristics and spatio-temporal distribution of fish near the waters of Uljin marine ranch area in the East Sea using hydroacoustics

Behavioral characteristics and spatio-temporal distribution of fish near the waters of Uljin marine ranch area in the East Sea using hydroacoustics

COMPOSITION, ABUNDANCE AND DISTRIBUTION OF NON-CICHLID FISH COMMUNITY IN OGBO STREAM AND ITS FLOODPLAIN, ENHWE, DELTA STATE, NIGERIA

A preliminary survey of the composition, abundance and distribution of non-cichlid fish community was carried out at Ogbo stream and its floodplain in Enhwe, Delta StateNigeria. Water samples and fishes were sampled and analyzed using APHA methods and standard fishing gear respectively. The physicochemical parameters revealed distinct values for station 1 (Temperature: 25.63°C, Transparency: 25.09 cm, Sulphate: 7.56 mg/L) and station 2 (Temperature: 23.60 °C, Transparency: 19.90 cm, Sulphate: 6.68 mg/L). Among the parameters, only Temperature, Transparency, and Sulphate exhibited a noteworthy difference (p<0.05) between the two stations. Transparency had a negative correlation with other parameters in Station 1.A total of 725 individual fish species belonging to eight families and genera were sampled. Among the notable findings, Clariidae emerged as the most abundant family, constituting 82.90% of the total relative abundance across both stations. Clarias camerunensisexhibited the highest abundance, comprising 62.20% of the total individuals sampled. Parachanna africanaand Clarias pachynemaalso demonstrated significant presence, contributing 15.00% and 13.20% to the total relative abundance, respectively. ANOVA indicates a significant difference in the composition and abundance of fish species between the stream and floodplain (p < 0.05), emphasizing the influence of habitat-specific factors. The Margalef’s richness (1.67), dominance (0.64), diversity (1.32) and evenness (0.34) index of fishes was higher in the stream than in the floodplains. Magnesium, sulphate, temperature, and transparency were positively correlated to the distribution patterns of Pantodon bucholzi, Clarias jaensis, Phractolaemus ansorgei, and Heterotis niloticusin station 1, with the exception of P. africanaand Polypterus senegalus. There was a negative association between dissolved oxygen, nitrate, pH, and Iron, and the distribution of fishes in station 2. Ogbo stream and its floodplain have low abundance and distribution of fish species. Therefore, it demands for sampling efforts and long-term studies to unravel the checklist of species

Quantifying the relative importance of biotic and abiotic factors in landscape-based models of stream fish distributions

Lotic fish species distributions are frequently predicted using remotely sensed habitat variables that characterize the adjacent landscape and serve as proxies for instream habitat. Recent advancements in statistical methodology, however, allow for leveraging fish assemblage data when predicting distributions. This is important because assemblage composition likely provides better information about instream habitat compared to landscape-derived metrics and therefore may improve predictions. To better understand the value of using multi-species fish data in species distribution modeling, we fit two conditional random fields (CRF) models to quantify the relative importance of fish assemblage co-occurrence, landscape-derived habitat variables, and interactions between these two predictor groups (i.e., effects of co-occurrence could be context-dependent) at over 1200 stream catchments in Pennsylvania, USA. We first compared predictive performance of CRF models against traditionally used single-species logistic regressions (generalized linear models; GLMs) and found that inclusion of fish assemblage data often improved predictive performance. The multi-species CRF models performed significantly better at predicting occurrence for 63% of species with an average percent increase in AUC of 25% compared to GLMs. Furthermore, the CRF identified species co-occurrences as more informative, and thus relatively more important, at predicting occurrence than the other effect types. The CRF also suggested that allowing these biotic effects to be context-dependent was important for predicting occurrence of many species. These findings illustrate the value of fish assemblage data for landscape-scale species distribution modeling and leveraging this information can improve predictions and inferences to help inform the management and conservation of freshwater fishes.

Determining Critical Points in Fish Distribution and Calculation of Income UD. Sumber Rezeki Laut, Tuban Regency

This study aims to evaluate the fish distribution activities in UD. Sumber Rezeki Laut, alongside the fish handling during distribution, and critical points of fish quality decline during distribution. This research uses descriptive analysis, critical point analysis, organoleptic tests, and income analysis. Distribution handling is divided into two types, namely direct distribution handling and indirect distribution handling. The most important handling of both types of distribution includes maintaining the right temperature during the process, transferring fish to UD. Sumber Rezeki Laut, changing fish containers, cleaning and soaking fish, and distributing fish to Balekambang Market. However, the long travel distance required to distribute the fishes has the potential to reduce the quality of the fish, as evidenced by the decrease in fish quality observed during the distribution trials. Organoleptic test results showed that the quality of the fish decreased from when it was purchased until it reached the wholesaler. Meanwhile, when calculating distribution costs, the highest result for direct distribution was IDR1,335,987, and the lowest was IDR372,995. The highest income from indirect distribution was IDR1,544,001, while the lowest was IDR399,993. To ensure good fish quality, UD. Sumber Rezeki Laut needs to improve its human resource capabilities to become more efficient and produce quality products for consumers.

Do fishers follow fish displaced by climate warming?

Climate change is associated with altered oceanographic conditions that tend to shift the geographical distributions of fish. To assess the impact of climate change on fisheries, one must go beyond projections of catch potential and understand how fishers respond to moving target species. Many previous studies have explicitly or implicitly assumed that fishers follow fish that are displaced by climate warming. Here, we evaluate this assumption by analyzing a long-term, large-scale yet high-resolution dataset combined with a detailed oceanographic model. Our study case is the Atlantic cod (Gadhus morhua) fishery in Norway, one of the largest whitefish fisheries in the world, with little technological or judicial constraints on the potential spatial response of fishers. An oceanographic model is used to predict the areas that have been suitable for Atlantic cod spawning over the two last decades. We compare whether these areas overlap with actually observed fishing locations. While the areas that are suitable for spawning clearly predict how much fish are caught per trip, the suitability of an area does not predict how many vessels fish in a given area at a given point in time. In contrast, the number of vessels in the previous week and the previous year explain the current number of vessels in that area. Hence, future projections of climate change effects should account for the rich and nuanced behavioral responses of humans to project climate change effects on fisheries.

Post‐Harvest Travels of Marine Fish: How Small Fish Food Systems Variously Support Food Security and Nutrition in Coastal and Inland Cities in Ghana

AbstractThis paper enquires into the travels of low‐cost varieties of marine fish in the context of Ghana, distinguishing flows that move toward coastal cities versus those destined for distant, inland cities. It derives data from field research on the Ghanaian small fish food system through surveys, FGDs and interviews conducted in Accra and Tamale. It is argued that although both coastal and inland cities partake in small fish food systems, they experience different flow patterns and FSN outcomes. These are partly related to the fact that Ghana relies on the confluence of local and imported sources for the delivery of low‐cost fish varieties to the population, especially in urban regions where such demand is high. We recommend that policies should focus on investing in infrastructure, especially transport and distribution systems linking cities to fishing communities, to enhance low‐cost fish distribution and improve FSN outcomes for low‐income urban consumers in Ghana.

Growth And Food Habits Of Pelian Fish Tor Douronensis Caught Using Tuba Root Poison In Krayan Nunukan, North Kalimantan

The use of semah fish with the local name pelian fish in nature is carried out using various methods, one of which is using tuba root plant poison. This tuba root poison is thought to have an impact on the biological condition of pelian fish and aquatic ecology. In connection with this, this research aims to analyze the size distribution, growth type and food habits of pelian fish. The research was conducted from June to August 2023 in West Krayan District, Nunukan Regency, North Kalimantan. The results of the study showed that the length distribution of pelian fish caught using tuba root plant poison was 30.626 ± 7.048 cm, with a weight of 786.531 ± 430.066 g. The growth pattern is negative allometric with eating habits consisting of moss at 44.57%, insects at 33.04%, pieces of fruit at 10.00% and unidentified at 12.39%. Moss and insects are the main food, while fruit is a complementary food. Based on the results obtained, pelian fish in nature can be caught using moss bait. The use of high doses of tuba root can cause damage to the fish's gills, which can cause fish death as a result of not being able to neutralize rotenone.

Assessment of the Carbon Footprint of Large Yellow Croaker Farming on the Aquaculture Vessel in Deep Sea in China

The present study conducted a Life Cycle Assessment (LCA) to evaluate the carbon emissions associated with large yellow croaker farming on Aquaculture Vessel “Conson No. 1”. The functional unit considered was 1 kg of fresh large yellow croakers delivered to a wholesaler. The life cycle of large yellow croaker farming on the aquaculture vessel was divided into five processes: feed production (FP), ship construction (SC), fingerling breeding (FB), adult fish farming (AF), and fish distribution (FD). Results showed that the carbon footprint (CF, kgCO2e/kg LW) for the complete life cycle amounted to 6.2170 kgCO2e/kg LW, while the CF per unit economic value of “Conson No. 1” large yellow croaker was estimated at 31 gCO2e/CNY. Among all processes, AF and FP had the highest CF contribution rates at 69.30% and 24.86%, respectively. Notably, energy consumption by aquaculture equipment on board emerged as the primary contributor across all sources of CF comparative analysis demonstrated that the CF of marine fish farming on the aquaculture vessel was lower than that of closed aquaculture systems’ average level and it was a viable option for implementing low-carbon aquaculture in the deep sea. In order to reduce energy consumption and promote a low-carbon economy in aquaculture vessels, several suggestions were proposed, including adjusting energy structure, enhancing energy efficiency, improving feed ratio, and optimizing feeding methods.

The Influence of Equal Employment Opportunities and Islamic Work Values on The Quality of Work LIfe of Employees CV. Profish International

Nowadays, several companies recognize the value of employee loyalty as one of the tools for their growth. Improving the quality of work life of employees is one approach to maintaining employee loyalty and increasing job satisfaction. The purpose of this study is to find out how the influence of equal employment opportunities and Islamic work values variables on the quality of work life. This research was conducted at CV. Profish Internasional which is a company that has a focus on the world of fisheries from cultivation to the distribution of fresh water fish. The population used in the study were all employees of C.V Profish Internasional, totaling 113 people. By using the Isaac and Michael formula, the sample in this study was 89 people. Data analysis used Patrial Least Square-Structural Equation Model or PLS-SEM analysis using SmartPLS. The results show that equality of employment opportunities and Islamic work values have a significant influence on the quality of work life of CV Profish International employees

Hotspots of the Habitats Directive species in the Carpathians

Knowledge of species distribution is crucial for their protection, and this was our motivation to identify hotspots of the Habitats Directive (HD) species in the Carpathians. As a data source we used reports and species distribution maps submitted by the EU Member States according to the Habitats Directive Article 17 in 2019.The highest HD species richness areas are in the south-eastern part of the Western Carpathians and in the south-west outcrops of the Carpathians at the SK/AT and CZ/AT borders. The south-eastern part of the Western Carpathians is important for all studied species groups, specific patterns of distribution exhibit fish (distribution along big rivers), amphibians (high diversity also in the outer Western Carpathians and Transylvanian Basin) and partially plant species (besides SE Western Carpathians, quite high diversity also in other parts of the Western Carpathians).We analysed the relation between species richness, proportion of species groups, and concentration of rare species. Mammals are the dominant taxonomical group, especially in species-poor grid cells. The proportion of invertebrates increases with increased species richness. The widespread species prevail in species-poor grid cells and their proportion decreases with increasing species richness.We also identified areas with low Natura 2000 coverage, but with high biodiversity or a high number of rare species. These areas have high potential to improve protection of the HD species by designating new Natura 2000 sites or enlarging existing ones.

Variability in coastal habitat available for Longfin Smelt Spirinchus thaleichthys in the northeastern Pacific Ocean

An understanding of oceanographic conditions and processes important to marine animal ecology is fundamental to the development of effective management and conservation actions. Longfin Smelt (Spirinchus thaleichthys) is a pelagic forage fish found in coastal and estuarine waters along the Pacific coast of North America from Alaska to central California. Substantial population declines in California’s San Francisco Estuary, where Longfin Smelt are protected under California’s Endangered Species Act, have prompted extensive study of estuarine factors associated with the decline. However, coastal factors that affect up to two-thirds of the Longfin Smelt life cycle are poorly understood and may be important drivers of population dynamics. We compiled coastal observations from numerous sources to estimate the range-wide coastal marine distribution of Longfin Smelt and assess habitat factors affecting distribution in the northeast Pacific Ocean. Based on maximum entropy species distribution models, Longfin Smelt distribution was correlated with depth, distance from the nearest estuary, sea surface temperature, and sea surface chlorophyll. Longfin Smelt were found in shallow, higher productivity coastal waters closer to estuaries, with depth and temperature the most consistent factors influencing distribution. Habitat suitability was highly variable at the southern extent of the range, particularly off the California coast, and was largely driven by habitat contractions associated with warm-water conditions. Study results provide insights into the habitat and range-wide distribution of an at-risk estuarine-reliant forage fish and are the first step toward identifying processes that affect the marine portion of the Longfin Smelt life cycle.

Long-term change in a North Sea inshore fish assemblage between 1899-1913 and 2018-2019

Marine communities have been impacted by human activities for centuries, yet historical data are rarely incorporated into modern conservation efforts and restoration targets. For inshore waters, survey data sets are typically lacking because they extend back by only a few decades, despite their ecological significance as nursery grounds for many fish species. We investigated long-term change in a demersal fish assemblage from inshore waters of the Northumberland coast (UK). We collated unique historical data (1899-1913) that were sampled using a wooden beam trawl during scientific trawling investigations, shortly after the onset of widespread mechanised trawling in the North Sea. Twelve decades later (2018-2019), we re-surveyed the same bays using a modern otter trawl. The results revealed marked declines in the abundance and diversity of the entire fish and flatfish assemblage as well as among individual species. Elasmobranchs and formerly abundant species such as grey gurnard Eutrigla gurnardus were completely absent in contemporary surveys, while dab Limanda limanda and plaice Pleuronectes platessa were the most dominant species in both periods. Changes were also detected in the size distributions of the entire fish and flatfish assemblages, with proportionally fewer large individuals recorded in contemporary surveys. These findings suggest that over a century of trawling and climate change, combined with pollution, habitat alteration and increased predation risk are likely contributors to changes in the inshore fish assemblage. This work provides further evidence of long-term decline in North Sea inshore waters and offers an invaluable benchmark for improving coastal ecosystem status.

On the probable distribution of stock-recruitment resilience of Pacific saury (Cololabis saira) in the Northwest Pacific Ocean

Abstract Determining how resilient a stock-recruitment relationship is to environmental variation is crucial for fisheries management. Steepness is a key factor characterizing the resilience of a fish stock and, hence, for establishing management reference points. This study estimates the distribution of steepness for Pacific saury using a simulation approach based on evolutionary ecology and reproductive biology, and how it changes in response to environmental change. The median estimated steepness is 0.82 (80% probable range 0.59, 0.93) based on the best available biological information, which suggests that Pacific saury can produce a relatively high proportion of unfished recruitment when depleted to 20% of unfished spawning biomass. Elasticity analysis indicates that steepness for Pacific saury is most sensitive to the survival rate of early life stages, mean body weight, growth, and length-at-maturity. Environmental change could substantially impact steepness, with unfavorable conditions related to survival rates, length-at-maturity, mean body weight, and growth potentially leading to a reduction in resilience. Understanding these impacts is crucial for the assessment and management of Pacific saury. Our numerical simulation approach provides an analytical tool applicable for calculating the steepness distribution in other small pelagic fish influenced by increases in sea surface temperature due to global warming.

Distribution and abundance of herbivorous reef fishes on a barrier reef system in the Florida Keys and Dry Tortugas, Florida

Herbivorous reef fishes control algal growth and are critical for maintaining reef health. Grazing effects vary due to community composition, so a diverse herbivore community is important for preventing phase shifts from coral to algal-dominated reefs. However, herbivore communities and grazing effects vary spatially, resulting in non-uniform distribution of algal mitigation across the seascape. Therefore, understanding how habitat influences herbivore communities is essential for predicting the spatial distribution of these species' ecological services. This study used underwater visual surveys (n = 5455) to examine how habitat influences spatial patterns of herbivorous fish densities and species richness in the Florida Keys and Dry Tortugas, Florida. Herbivorous fishes were ubiquitous, and communities were dominated by small herbivores such as damselfishes (Pomacentridae), gobies (Gobiidae), surgeonfishes (Acanthuridae), and small- to medium-bodied parrotfishes (subfamily Scarinae). A suite of factors influenced herbivorous fish communities but boosted regression tree results showed that habitat relief, depth, and spatial location within the Florida Keys and Dry Tortugas were the most important factors. In general, herbivore occurrence, density, and species richness increased as percent of low relief hardbottom habitat (<0.2 m high) decreased. In addition, density and occurrence of herbivores generally increased at shallower depths. Spatial location influenced the density of herbivores with potential hotspots predominantly located in the Upper Keys and the Dry Tortugas Bank. These data provide a valuable understanding of the spatial distribution of herbivorous reef fishes, and aid management decisions regarding the protection and sustainability of herbivore resources and the ecosystems that rely on them.

Sport fish movement responses to a littoral zone coarse woody habitat addition

AbstractObjectiveFish movements and distributions throughout an ecosystem are important for understanding ecological interactions, conservation, and management. Coarse woody habitat (CWH) additions are a popular habitat enhancement tool that can influence movements and distributions of fishes; however, behavioral responses in relation to CWH additions are understudied. The objectives of our study were to test for changes in habitat use and behavioral responses of Muskellunge Esox masquinongy, Smallmouth Bass Micropterus dolomieu, and Walleye Sander vitreus to CWH additions in a small inland northern lake over 3 years and to evaluate two common forms of fish tracking to estimate daily movement of these fishes.MethodsWe used passive integrated transponder tag data collected continuously at 10 littoral sites and radiotelemetry data collected biweekly during the summer–fall months prior (2017) and following (2018–2019) CWH addition to examine movement behaviors and estimate daily probability of movement for the three species among lake habitats using multistate models.ResultWalleye were the most likely to remain near CWH, followed by Smallmouth Bass and Muskellunge. All species were more likely to move away from the modified and unmodified littoral zones and were more likely to remain in the offshore zone. Increased movement of fish may be in response to CWH creating a refuge for forage fish and subsequent increases in prey search times.ConclusionOur results suggest that CWH additions may alter established species‐specific annual movements, distributions, and habitat use to differing degrees in ecosystems, as our results differ from other CWH studies. Methodologically, radio‐tagging was most effective for offshore tracking but most labor intensive. Novel passive integrated transponder arrays (less labor intensive once installed) worked well to monitor movement between habitat types in shallow littoral areas. Long‐term monitoring of behavioral changes will be essential to assessing the stability changes caused by these habitat alterations.

Machine-learning aiding sustainable Indian Ocean tuna purse seine fishery

Among the various challenges facing tropical tuna purse seine fleet are the need to reduce fuel consumption and carbon footprint, as well as minimising bycatch of vulnerable species. Tools designed for forecasting optimum tuna fishing grounds can contribute to adapting to changes in fish distribution due to climate change, by identifying the location of new suitable fishing grounds, and thus reducing the search time. While information about the high probability to find vulnerable species could result in a bycatch reduction. The present study aims at contributing to a more sustainable and cleaner fishing, i.e. catching the same amount of target tuna with less fuel consumption/emissions and lower bycatch. To achieve this, tropical tuna catches as target species, and silky shark accidental catches as bycatch species have been modelled by machine learning models in the Indian Ocean using as inputs historical catch data of these fleets and environmental data. The resulting models show an accuracy of 0.718 and 0.728 for the SKJ and YFT, being the absences (TPR = 0.996 for SKJ and 0.993 for YFT, respectively) better predicted than the high or low catches. In the case of the BET, which is not the main target species of this fleet, the accuracy is lower than that of the previous species. Regarding the silky shark, the presence/absence model provides an accuracy of 0.842. Even though the model's performance has room for improvement, the present work lays the foundations of a process for forecasting fishing grounds avoiding vulnerable species, by only using as input data forecast environmental data provided in near real time by earth observation programs. In the future these models can be improved as more input data and knowledge about the main environmental conditions influencing these species becomes available.

Evolution of the ecological niche behind the largest disjunct freshwater fish distribution in the world.

Ecological processes that are behind distributions of species that inhabit isolated localities, complex disjunct distributions, remain poorly understood. Traditionally, vicariance and dispersion have been proposed as explanatory mechanisms that drive such distributions. However, to date, our understanding of the ecological processes driving evolution of ecological niches associated with disjunct distributions remains rudimentary. Here, we propose a framework to deconstruct drivers of such distribution using World's most widespread freshwater fish Galaxias maculatus as a model and integrating marine and freshwater environments where its life cycle may occur. Specifically, we assessed ecological and historical factors (Gondwanan vicariance, marine dispersion) and potential dispersion (niche-tracking) that explain its distribution in the Southern Hemisphere. Estimated distribution was consistent with previously reported distribution and mainly driven by temperature and topography in freshwater environments and by primary productivity and nitrate in marine environments. Niche dynamics of G. maculatus provided evidence of synergy between vicariance and marine dispersion as explanatory mechanisms of its disjunct distribution, suggesting that its ecological niche was conserved since approximately 30 Ma ago. This integrated assessment of ecological niche in marine and freshwater environments serves as a generic framework that may be applied to understand processes underpinning complex distributions of diadromous species.

Environmental conditions on the Pacific halibut fishing grounds obtained from a decade of coastwide oceanographic monitoring, and the potential application of these data in stock analyses

Context Establishing baseline environmental characteristics of demersal fish habitat is essential to understanding future distribution changes and to identifying shorter-term anomalies that may affect fish density during monitoring efforts. Aims Our aim was to synthesise environmental data to provide near-bottom oceanographic baseline information on the Pacific halibut fishing grounds, to establish geographic groupings that may be used as co-variates in fish-density modelling and to identify temporal trends in the data. Methods Water-column profiler data were collected from 2009 to 2018 along the North American continental shelf, during summer fishery surveys focused on Pacific halibut. Key results In addition to establishing baseline information on the fishing grounds, this analysis illustrated that environmental variables can be grouped geographically into four regions that correspond to the four biological regions established by the International Pacific Halibut Commission. A spatio-temporal modelling approach is presented as an example of how to describe the relationship between environmental data and Pacific halibut distribution. Conclusions This study has highlighted the efficacy of environmental data in analysing fish distribution and density changes. Implications Oceanographic monitoring provides the ability to detect annual anomalies such as seasonal hypoxic zones that may affect fish density and to establish baseline information for future research.

Strategi Pengembangan Usaha Bibit Ikan Lele Ditinjau Dari Perspektif Ekonomi Islam (Studi Kasus Di Kabupaten Tanggamus)

In the business world, marketing is an integral part. However, in sharia marketing, the entire process must be in accordance with the contracts and principles of muamalah in Islam. The development of the catfish seedling business in Tanggamus Regency still has several challenges that need to be overcome. To overcome these challenges, an appropriate business development strategy is needed, one of which is by applying an Islamic economic perspective. The Islamic economic perspective can provide guidelines in the development of a more sustainable and fair catfish seed business. This study applies qualitative research methods to explore the phenomena and problems in the catfish seed farming business in Tanggamus Regency. The focus was on understanding the challenges faced by farmers and relevant catfish seedling business development strategies. Through in-depth interviews and field observations, researchers gained insights into the Islamic economic strategies applied in the production, marketing and distribution of catfish seedlings. The results show that catfish seedling farming in Tanggamus Regency, Lampung, follows Islamic principles in its development strategy. Based on the values of honesty, sincerity, professionalism, good relations, holy intentions, as well as the obligations of zakat, infaq, and sadaqah, the business process is in accordance with the principles of Islamic Economics, which emphasizes ethics in running a business. The strategies implemented, such as the application of Good Breeding Practices (GBP) to ensure the quality of fish seeds, fair pricing, and distribution that expands the market without oppressing others, are a form of implementation of Islamic values in business practices.