The Spatial Variation of Acoustic Water Column Data and Its Relationship with Reef-Associated Fish Recorded by Baited Remote Underwater Stereo-Videos off the Western Australia Coast

Spatially explicit information on coral fish species abundance and distribution is required for effective management. Nonextractive techniques, including echosounders and video census, can be particularly useful in marine reserves where the use of extractive methods is restricted. This study aimed to investigate the possibility of combining echosounders and baited remote underwater stereo-videos (stereo-BRUVs) in providing more holistic information on the distribution of demersal and semidemersal reef-associated fish. The spatial distribution of fish biomass was assessed using both methods in two small areas, one in Cockburn Sound (CS), a temperate body of water, and the other in the tropical waters of the Ningaloo Marine Park (NMP). The results showed high correlations between the acoustic and stereo-BRUV data in CS, suggesting the potential use of both for a better estimation of biomass in the area. The results for the NMP showed weaker correlations between the two datasets and highlighted the high variability of the system. Further studies are required, but our initial findings suggest a potential benefit of combining both techniques in the reef-associated fish distribution assessment.

Design of Prototype Information System for Tracking & Tracing Fish Distribution Based on Mobile Agent

The National Fish Logistics System or often called SLIN is an Indonesian Ministry of Maritime Affairs and Fisheries program that aims to maintain the stability of the production and marketing systems and control the disparity in national fish prices. Central Sulawesi is the Province that becomes the main corridor of this program. The inefficient distribution monitoring process generally causes several problems in the field of fisheries distribution management that still often occur today by the regional Ministry of Maritime Affairs and Fisheries. It indicates that SLIN is not yet running optimally. This study purpose a prototype design of fish distribution tracking based on a mobile agent that can use to help consumers to track distribution channels and get information about the origin of the fish to be purchased. The data will further process for monitoring fish distribution in a real-time manner by the regional Ministry of Maritime Affairs and Fisheries. A proper monitoring mechanism will undoubtedly help the government in making policies and conducting supervision to make the SLIN implementation successful in Central Sulawesi. By the research, we found that the proposed method can gather data from every level fish distribution agent then processed the data to inform about distribution line and the origin of the fish for the consumer. The proposed solution framework could be implemented and nearly fit with current implementation criteria. The framework later can be a base framework for developing a more advanced information system for SLIN in Central Sulawesi Region.

A comparative study of small-scale fishery supply chains’ vulnerability and resilience to COVID-19

The COVID-19 pandemic and response has significantly disrupted fishery supply chains, creating shortages of essential foods and constraining livelihoods globally. Small-scale fisheries (SSFs) are responding to the pandemic in a variety of ways. Together, disruptions from and responses to COVID-19 illuminate existing vulnerabilities in the fish distribution paradigm and possible means of reducing system and actor sensitivity and exposure and increasing adaptive capacity. Integrating concepts from literature on supply chain disruptions, social-ecological systems, human wellbeing, vulnerability, and SSFs, we synthesize preliminary lessons from six case studies from Indonesia, the Philippines, Peru, Canada, and the United States. The SSF supply chains examined employ different distribution strategies and operate in different geographic, political, social, economic, and cultural contexts. Specifically, we ask (a) how resilient have different SSF supply chains been to COVID-19 impacts; (b) what do these initial outcomes indicate about the role of distribution strategies in determining the vulnerability of SSF supply chains to macroeconomic shocks; and (c) what key factors have shaped this vulnerability? Based on our findings, systemic changes that may reduce SSF vulnerability to future macroeconomic shocks include: diversification of distribution strategies, livelihoods, and products; development of local and domestic markets and distribution channels; reduced reliance on international markets; establishment of effective communication channels; and preparation for providing aid to directly assist supply chains and support consumer purchasing power.

Past, Current and Future of Fish Diversity in the Alakol Lakes (Central Asia: Kazakhstan)

The aboriginal ichthyofauna of the Balkhash basin consists mainly of endemic fish species. By the end of the last century, indigenous fish species were driven out of Lake Balkhash and the Alakol Lakes remain the largest refuges of aboriginal fish fauna. Knowledge of regularities of the modern distribution of the indigenous fishes is crucial for biodiversity conservation as well as restoring aquatic ecosystems. The modern diversity of fish species was investigated there in this study. Significant changes for the indigenous and some alien fish distributions were revealed in contrast with earlier known data. Canonical correspondence analysis (CCA) was used to study the relationships between habitat characteristics and species abundance. Water mineralization and maximal observed water temperatures were estimated as the main environmental variables in fish distribution at the local scale. Habitat change leads to fish fauna homogenization as a result of rare species extinction and alien penetration. Growing human population and poor water management make the future of the indigenous fishes unpredictable.

Reconnecting the Elwha River: Spatial Patterns of Fish Response to Dam Removal

The removal of two large dams on the Elwha River was completed in 2014 with a goal of restoring anadromous salmonid populations. Using observations from ongoing field studies, we compiled a timeline of migratory fish passage upstream of each dam. We also used spatially continuous snorkeling surveys in consecutive years before (2007, 2008) and after (2018, 2019) dam removal during summer baseflow to assess changes in fish distribution and density over 65 km of the mainstem Elwha River. Before dam removal, anadromous fishes were limited to the 7.9 km section of river downstream of Elwha Dam, potamodromous species could not migrate throughout the river system, and resident trout were the most abundant species. After dam removal, there was rapid passage into areas upstream of Elwha Dam, with 8 anadromous species (Chinook, Coho, Sockeye, Pink, Chum, Winter Steelhead, Summer Steelhead, Pacific Lamprey, and Bull Trout) observed within 2.5 years. All of these runs except Chum Salmon were also observed in upper Elwha upstream of Glines Canyon Dam within 5 years. The spatial extent of fish passage by adult Chinook Salmon and Summer Steelhead increased by 50 km and 60 km, respectively, after dam removal. Adult Chinook Salmon densities in some previously inaccessible reaches in the middle section of the river exceeded the highest densities observed in the lower section of the river prior to dam removal. The large number (>100) of adult Summer Steelhead in the upper river after dam removal was notable because it was among the rarest anadromous species in the Elwha River prior to dam removal. The spatial extent of trout and Bull Trout remained unchanged after dam removal, but their total abundance increased and their highest densities shifted from the lower 25 km of the river to the upper 40 km. Our results show that reconnecting the Elwha River through dam removal provided fish access to portions of the watershed that had been blocked for nearly a century.

Fish Assemblages in a Small Mangrove System on Príncipe Island, Gulf of Guinea

Mangroves are highly productive ecosystems with complex adaptations to the transition between freshwater and sea. Mangroves function as nursery habitats for many organisms, providing protection and food sources for early developmental stages of crustaceans and fish, helping to maintain adjacent marine stocks. Mangroves in São Tomé and Príncipe remain poorly studied. This study addresses the importance of a small mangrove stand to ichthyofauna. The main goal of the study was to describe the fish assemblages of the Praia Salgada mangrove stand on Príncipe Island, and assess if variations in the season, tide, and mangrove zone affected fish distribution. Fish assemblages were sampled with mosquito nets during the rainy and dry seasons, and neap and spring tides, while environmental parameters such as water depth, temperature, pH, and salinity measurements were taken. The characteristics of the water column were affected by a sandbank that developed between sampling seasons, impacting on the dynamics of the water and biological exchanges between the mangrove stand and the adjacent marine environment. The study identified 14 fish species occurring in the Praia Salgada mangrove stand from a total of 772 specimens caught. Five species were recorded for the first time as occurring in the country’s mangrove areas, namely Caranx latus, Ethmalosa fimbriata, Mugil curema, Gobioides cf. africanus, and Citharus cf. linguatula. Most of the reported species are of commercial interest, and were predominantly juveniles, suggesting that the mangrove ecosystem provides a nursery function for several species. Some species revealed preferences for either the upper or lower part of the mangrove forest. The size of fish sampled tended to be bigger during the dry season, especially for the Mugilidae, Aplocheilichthys spilauchen and Gobiidae groups. E. fimbriata and Eucinostomus melanopterus displayed similar sizes between seasons. The average quantity of fish caught per day in the rainy season was three times higher than in the dry season. The fish species distribution in the mangrove stand varied significantly according to the season and mangrove zone. The overall results suggest that the Praia Salgada mangrove stand provides a nursery function for several of the studied fish species.

Seasonal coastal upwelling in the Bali Strait: a model study

Bali Strait is part of fisheries management zone (WPP 573), where abundant fishery potential, of lemuru fish commodity. Here, physical oceanographic setting such as upwelling event plays an important role on maintaining high primary productivity and lemuru fish distribution. This study aims to describe physical process and dynamics of seasonal coastal upwelling using time-series datasets (2008 and 2014) of temperature, salinity, current velocity, surface chlorophyll-a (chl-a) from INDESO model and satellite imagery. The results showed that upwelling in the Bali Strait only during the southeast monsoon period when the south-easterly wind force surface Ekman drift of about 5.5 × 10−3 Sv flowing south-eastward (toward offshore). Upwelling event is characterized by minimum parameter of sea surface temperature (24.93 °C), and sea level anomaly (0.75 m), but maximum of surface chlorophyll-a (1.33 mg/m3). Furthermore, isotherm of 26 °C and Isohaline 33.7 psu are outcropped at sea surface in the center of upwelling zone. In contrast, during the nortwest monsoon period these isolines remain at deeper layer of about 80-90 m depth. Mean temperature-based upwelling index during peak of upwelling in August (1.19±0.19 °C). Upwelling impact on high abundance of lemuru fish (Sardinella sp.) production two month later after peak of chl-a.

Impact Des Aménagements Hydroélectriques Sur Le Peuplement Des Poissons Du Lac De Barrage De Buyo Et De La Zone Périphérique (Côte d’Ivoire)

L’objectif de ce travail était de déterminer l’impact des variations des niveaux d’eau sur la distribution des poissons dans le lac de Buyo et le cours principal du fleuve Sassandra. Les campagnes ont lieu de Juin 2018 à Mai 2019. Les changements hydrologiques ont été observés après la mise en eau d’un deuxième barrage sur le fleuve Sassandra. Ces changements hydrologiques ont eu un impact sur la diversité piscicole. Les poissons ont été capturés à l’aide des filets maillants et des nasses artisanales. Ces poissons sont repartis en 6 ordres, 14 familles et 42 espèces. Dans le lac de Buyo, l’espèce Synodontis punctifer domine le peuplement en période de crue alors que Coptodon zillii est prépondérante en période de décrue. Dans le cours principal l’espèce Synodontis punctifer domine le peuplement durant les périodes d’ouverture et de fermeture des vannes du barrage, cette espèce est plus adaptée aux changements hydrologiques. Une bonne organisation du peuplement est observée en période de crue dans le lac. Dans le cours principal, une bonne organisation du peuplement est avérée en période de décrue lorsque les vannes du barrage sont fermées. Le modèle de prévision a montré que dans le lac de Buyo, la richesse spécifique est influencée positivement les cotes de retenue mais négativement par le débit d’apport d’eau et le volume d’eau déversé. Dans le milieu fluviatile, le modèle a montré que la richesse spécifique est influencée négativement par la profondeur et le débit d’eau turbiné mais influencé positivement par la vitesse du courant. The objective of this work was to determine the impact of water level variations on fish distribution in Lake Buyo and the main course of the Sassandra River. The campaigns will take place from June 2018 to May 2019. The hydrological changes are proven after the impoundment of a second dam on the Sassandra River. These hydrological changes have had an impact on fish diversity. The fish were caught using gillnets and artisanal traps. These fish are divided into 6 orders, 14 families and 42 species. In Lake Buyo, the species Synodontis punctifer dominates the population during the flood period while Coptodon zillii is predominant during the low water season. In the mainstream, the species Synodontis punctifer dominates the population during the periods of opening and closing of the gates of the dam, this species is more adapted to hydrological changes. A good organization of the population is observed during the period of flooding in the lake. In the main river, a good organization of the population is proven during the flood period when the gates of the dam are closed. The predictive model showed that in Lake Buyo, the species richness is positively influenced by the impoundment rating but negatively by the inflow rate and the volume of water discharged. In the fluvial environment, the model showed that the specific richness is negatively influenced by the depth and the turbinated water flow but positively influenced by the current speed.

Can Identifying Discrete Behavioral Groups With Individual-Based Acoustic Telemetry Advance the Understanding of Fish Distribution Patterns?

Identifying patterns of organismal distribution can provide valuable insights for basic and applied marine and coastal ecology because understanding where animals are located is foundational to both research and science-based conservation. Understanding variation in distributional patterns can lead to a better assessment of ecological drivers and an improved ability to predict consequences of natural and altered relationships. Here, our purpose is to explore if quantifying coexisting groups of individual fish predators advances our understanding of field distribution patterns. Toward this end, we quantified locations of 59 acoustically tagged striped bass (Morone saxatilis) within a 26-stationary unit telemetry receiver array in Plum Island Estuary (PIE), MA, United States. We then used cluster analyses on spatial and temporal-spatial metrics from this dataset to (1) assess if distinct groups of individuals coexisted, (2) quantify group characteristics, and (3) test associations between groups and distribution (e.g., physical site type and region). Based on multiple lines of evidence, we identified four groups of striped bass with different space use patterns that persisted across seasons (summer and fall). Similar-sized striped bass clustered at spatial and temporal scales at which individuals within distinct groups could, and did, physically overlap. In addition, distributional groups were linked to components of physical site type and region suggesting that discrete groups of individuals can interact differently with the environment within the same ecological system. The identification of these distinct groups of individuals creates a baseline from which to explore further ecological implications of grouping behavior for research and conservation in geographically large, temporally dynamic, and spatially heterogeneous marine and coastal environments.