Local Fish Research Articles

Estimating the extent of urchin barrens and kelp forest loss in northeastern Aotearoa, New Zealand

ABSTRACT On shallow rocky reefs in northeastern Aotearoa, New Zealand, urchin barrens are indicators of the ecosystem effects of overfishing reef predators. Yet, information on their extent and variability is lacking. We use aerial imagery to map the urchin barrens and kelp forests on reefs (<30 m depth) across seven locations, including two long-established marine reserves and a marine protected area that allows recreational fishing. Urchin barrens were present in all locations and were restricted to reefs <10–16 m deep. Urchin barrens covered 30% (7–49%) of shallow reefs in fished areas, with variation among and within locations likely related to the relative extent and topography of reefs and wave exposure. Within the marine reserves, barrens covered <2% of shallow reefs. Long-term comparison of historical imagery at two fished locations demonstrates that current areas of urchin barrens were historically dominated by kelp forests, but barrens have persisted since at least the early 2000s. We estimate ∼30 km2 of barrens exist across the region. This demonstrates the widespread nature of barrens, the potential long-term effectiveness of no-take marine protection in restoring urchin barrens, and the need for a multifaceted management approach to restore kelp forests and prevent further expansion of barrens.

Measuring Total Mercury Level in Local Food Fish Bangamary (Macrodon ancylodon) in Guyana

This research conducted in 2019 at the University of Guyana investigated the content of methylmercury in local food fish Macrodon ancylodon locally known as Bangamary. A total of 24 samples of M. ancylodon was purchased from the Meadow Bank Wharf in Guyana for analysis of total mercury level. Additionally, the size frequency at which mercury concentration is the highest was also evaluated. The results indicated that total mercury concentration in each sample of M. ancylodon was less than 0.5 mg/kg. With an average total mercury content of 0.10 mg/kg, adults had the greatest total mercury content, followed by juveniles (0.06 mg/kg) and young (0.02 mg/kg). This may be attributed to the carnivorous diet of M. ancylodon and the fact that the fish species is usually captured in the estuarine regions of the Demerara and Essequibo Rivers. These waterways are linked to mining areas in Guyana's interior region that discharge mercury contaminated water, which could be the reason why mercury is bioaccumulating in the tissue of the Bangamary.

Incorporation of abandoned and lost fishing gear into the structure of Dendrophyllia ramea in the Atlantic coast of Portugal

Plastic pollution poses global and societal concerns, especially from discarded fishing gear, threatening seabed environments like coral reefs. This study examines the incorporation of lost and/or abandoned fishing gear - specifically synthetic lines, and filaments - into the structure of orange tree coral, Dendrophyllia ramea along the coast of Portugal, in the North-East Atlantic Ocean. The specimens were inadvertently captured by local fishers (Sines and Cascais), with 6 % showing filaments inside their structure, raising questions about their potential impact on coral health. We discuss the implications of understanding the interactions between plastics, fishing gear, and corals, which is important for developing conservation strategies. We address the need for improved of measures aimed at reducing the impact of fishing gear on corals, emphasizing the importance of endorsing biodegradable fishing materials and supporting lost gear retrieval initiatives. Furthermore, we emphasize the urgent need to communicate these issues to both fishers and stakeholders.

Stock assessment and fishing management of green abalone (Haliotis fulgens) along the West Coast of Baja California Sur, Mexico

The green abalone fishery in Mexico has showed declines in the availability of the resource, but the current state of the population is unknown. The aim of this study was to analyze inter-annual variation in recruitment, mortality, total and vulnerable biomass, selectivity, and harvest rate of Haliotis fulgens. A size-structured model was used to assess changes in the population dynamics and management quantities from 2010 to 2019. The model describes the exploitation and growth of individuals in the population, and incorporates a stochastic growth matrix that defines the variation in the length increments of individual to individual. Key results indicated that the recruitment failures occurred in infrequent pulses of varying intensity. Moreover, a slight recovery of total biomass during 2017 (791 t), 2018 (1496 t), and 2019 (1274 t) was observed after a slight increase in recruitment and a decrease in harvest rate. The vulnerable biomass increased 44.38% from 2010 to 2019. The harvest rate revealed that individuals larger than the minimum legal size of 145 mm were under high fishing pressure. The stock assessment model highlights an adverse effect in the population; given the deteriorating conditions of the green abalone fishery, it is imperative to transition fully to a recovery strategy, including all the administrative zones in the assessment and management. The adoption of proactive strategies such as the establishment of reference points, no-fishing reserves, and the implementation of a farming system would facilitate the protection of critical abalone populations, contributing to their medium-term recovery, and would be an economic alternative for local fishers.

Impacts of stony coral tissue loss disease on the persistence of Caribbean cleaner gobies

Because they serve as the main architects of coral reefs, the distribution and abundance of stony coral species have major impacts on other associated community members. Thus, coral diseases can have significant cascading effects throughout the ecosystem. Stony coral tissue loss disease (SCTLD) is the most recent of many diseases documented to impact Caribbean stony corals. SCTLD is known to impact over 20 species of reef-building corals and can cause complete colony mortality of large corals in only one month. Among the coral species impacted are those occupied as cleaning stations by Caribbean cleaner gobies. This study examined the persistence of these gobies on living coral cleaning stations where SCTLD was most recently or not yet affected (emergent), recently established (epidemic), and well-established (endemic),. Timed surveys were conducted at nine reefs in the U.S. Virgin Islands between October 2019 and March 2021. Study sites were surveyed both before and after the outbreak/establishment of SCTLD where possible. Monitoring sites were established at six reefs by tagging 25 live coral cleaning stations at each of two endemic and two epidemic sites and 50 cleaning stations at each of two emergent sites. Goby abundance at each site was monitored at least five times from March 2020 to April 2021. Timed surveys found cleaner goby abundance was 50% lower in the endemic zone compared to epidemic and emergent zones. Overall, goby abundance declined on tagged cleaning stations throughout the course of this study at all sites. However, overall goby density within monitored areas remained stable across most sites from the beginning to the end of the study. One emergent site experienced a two-fold increase in goby density and one epidemic site experienced a decline in goby density. This suggests that gobies are remaining at the site but may be abandoning live coral cleaning stations as the individual colonies are affected by SCTLD. Given the benefit cleaner gobies have on local coral reef fishes, changes in cleaning activity associated with coral disease have the potential to negatively impact Caribbean reef fish communities.

Population aspects of Crassostrea sp. in a protected mangrove estuary: perspectives for artisanal fishing management

ABSTRACT The mangrove oyster (Crassostrea) is one of the most common bivalves found on the Brazilian coast, widely used in artisanal fisheries. Oysters are dioecious with external reproduction, typically found in estuarine environments. The present study aimed to identify the population aspects of Crassostrea in different fishing locations in northeastern Brazil. The study area was the Acaú-Goiana Extractive Reserve, a protected area focused on the development of artisanal fisheries. Oysters were collected during low tide at three sampling points, where their removal from mangrove roots was carried out, during May, July, September, November 2021, and January and March 2022. In the laboratory, biometric measurements were conducted, and for the months of May and November 2021 histological preparations to study the reproductive cells. Biometric measurements were significantly higher in the dry season at all sampling points. The sex ratio was M = 0.38, F = 0.62, for May, and M = 0.30, F = 0.69, for November. The biometric and reproductive data obtained can support the development of management strategies, including a rotation plan between collection sites and the establishment of a minimum size for fishing. Here we recommend a minimum size of 20 mm shell length (SL) or larger for fishing.

Replacing artisanal fisheries with dolphin watching: Strategy for conservation and sustainable community‐based marine ecotourism

Abstract In coastal delphinid conservation, dolphin watching (DW) is frequently proposed for artisanal fishers as a community‐based marine ecotourism (CBME) plan to reduce fishing effort and delphinid bycatch. Questions including whether DW profitability is sufficient to replace fishing and whether fishers can conduct DW sustainably, however, are rarely examined. In the present study, questionnaire targeting tourists was implemented to investigate DW profitability in Sanniang Bay, China where DW‐based CBME has been operated by local fishers since 2004. CBME sustainability was evaluated by comparing DW profitability with household income with reference to local poverty, and rural and economically comfortable families in China. Out of 1046 tourists interviewed, 40 (3.82%) tourists knew there is DW in Sanniang Bay, while 292 (27.9%) tourists were lured to attend DW with low pricing. The fisher earned 110RMB (ca. 16.0$USD) per DW trip and required two, four, and nine trips per day to earn household income higher than poverty, rural and economically comfortable lines. Raising ticket fee and maximizing per‐trip number of tourists can substantially improve DW profitability, which facilitates CBME sustainability and poses minimal impacts on target animals. CBME in rural areas could be trapped into low popularity–low pricing–low profitability embarrassments because of primitive tour facilities, insufficient ecological education value, poor hospitality skills and lacking marketing access. The sustainable CBME should incorporate ecologically friendly conducts, direct indigenous profits with minimal transaction costs, venture and service diversification, and marketing with indigenous cultural characteristics. DW history in Sanniang Bay further indicates profit distribution of tourism ventures directly influence CBME sustainability. Accordingly, indigenous rights, economic equity and social justice should be centrally placed in CBME policying with the minimal intervention from non‐indigenous capitals and commercialized manipulations.

Planning and implementing genetic rescue of an endangered freshwater fish population in a regulated river, where low flow reduces breeding opportunities and may trigger inbreeding depression.

Augmenting depleted genetic diversity can improve the fitness and evolutionary potential of wildlife populations, but developing effective management approaches requires genetically monitored test cases. One such case is the small, isolated and inbred Cotter River population of an endangered Australian freshwater fish, the Macquarie perch Macquaria australasica, which over 3 years (2017-2019) received 71 translocated migrants from a closely related, genetically more diverse population. We used genetic monitoring to test whether immigrants bred, interbred with local fish and augmented population genetic diversity. We also investigated whether levels of river flow affected recruitment, inbreeding depression and juvenile dispersal. Fish length was used to estimate the age, birth year cohort and growth of 524 individuals born between 2016 and 2020 under variable flow conditions. DArT genome-wide genotypes were used to assess individual ancestry, heterozygosity, short-term effective population size and identify parent-offspring and full-sibling families. Of 442 individuals born after translocations commenced, only two (0.45%) were of mixed ancestry; these were half-sibs with one translocated parent in common. Numbers of breeders and genetic diversity for five birth year cohorts of the Cotter River fish were low, especially in low-flow years. Additionally, individuals born in the year of lowest flow evidently suffered from inbreeding depression for juvenile growth. The year of highest flow was associated with the largest number of breeders, lowest inbreeding in the offspring and greatest juvenile dispersal distances. Genetic diversity decreased in the upstream direction, flagging restricted access of breeders to the most upstream breeding sites, exacerbated by low river flow. Our results suggest that the effectiveness of translocations could be increased by focussing on upstream sites and moving more individuals per year; using riverine sources should be considered. Our results indicate that river flow sufficient to facilitate fish movement through the system would increase the number of breeders, promote individuals' growth, reduce inbreeding depression and promote genetic rescue.

A new record of the invasive vermiculated sailfin catfish Pterygoplichthys disjunctivus in the Wainganga River, Eastern Maharashtra, India

This study documents the presence of an exotic loricariid catfish species, Pterygoplichthys disjunctivus (Weber, 1991), in the Wainganga River of Maharashtra, India. Originally native to South America, sailfin catfish are now commonly used as ornamental fish beyond their natural habitat. The species was observed near Gosekhurd Dam (20°52'15"N and 79°37'00"E) along the Wainganga River. Two individual specimens were collected during the study, with an average total length (320.31-338.63 mm) and weight (500.21-540.31 g). The rapid expansion of these species and its potential impact on local fish populations and inland fishing resources have raised concerns. Immediate preventive measures are necessary to control the establishment and subsequent uncontrolled spread of P. disjunctivus, may be imminent which would be pose a threat to the freshwater biodiversity of the River Wainganga. Effective management strategies should be implemented to preserve the natural habitat of these species. This study provides the first documented occurrence of P. disjunctivus, a member of the Loricariidae, near the Gosekhurd dam on the Wainganga River in Maharashtra, India.

Evaluating the Sustainability of an Eastern Mediterranean Gillnet Fishery Based on the Catches of Undersized Individuals and the Reproductive Period of Targeted Species

The catch composition of a coastal gillnet fishery in the Eastern Mediterranean Sea was analyzed through a two-year experimental fishing survey. Seven fish species occurred regularly in the hauls. Surmullet, Mullus surmuletus, which is the most valuable demersal fish in Greek waters and the intended target of the gillnets in small-scale fisheries, was the most abundant and systematically caught species. Almost all surmullets were larger than their minimum conservation reference size. However, three commercially exploited species (Diplodus annularis, Pagellus acarne, and P. erythrinus) were caught systematically as undersized individuals. In addition, these three species were caught mostly as immature individuals. Moreover, the operational season of the surveyed métier overlapped completely with the reproductive period of five commercially exploited species (D. annularis, M. barbatus, M. surmuletus, Sphyraena sphyraena, and Trachurus trachurus). Improvements and the establishment of additional technical measurements should be considered for the small-scale gillnet fisheries in the studied area to attenuate their detrimental effects and achieve a better compromise between sustainable exploitation of the local multi-species fish resources and the need for an economically sustainable practice.

A multi-scale tracking approach for conserving large migratory fish in an open coastal environment

Coastal habitats serve essential roles in the life cycles of migratory fishes, impacting both local and regional population stability. Conservation efforts for coastal fish often rely on spatial approaches within designated boundaries to mitigate threats and enhance production. However, in open coastal environments, migratory behaviours can extend beyond these protected areas, exposing individuals to potential threats or population bottlenecks elsewhere in their range. To improve conservation outcomes, a comprehensive understanding of movements across the entire migratory range is essential. Aquatic telemetry is a valuable tool for studying these behaviours, but must be adapted to address questions at multiple spatial and temporal scales. In this study we demonstrate how a combination of telemetry techniques can capture both local and regional fish behaviours. We begin by introducing the implications of migratory behaviours for fish conservation in open coastal environments, using the Wadden Sea as an example where additional research and management are needed to address fish declines. We then present a case study which uses the Dutch Wadden Sea to illustrate how a multi-scale telemetry approach can enhance both fundamental knowledge and conservation strategies for migratory fish. Within this case study, we present the general movement strategies exhibited by coastal migrants, alongside an overview of telemetry techniques applicable for open coastal systems. We then apply a size-based assessment using a reference tag to estimate the suitability of common Wadden Sea species for long-term tracking. Drawing from these results, we select four example species to showcase how species-specific understanding of fish life history and abundance can guide tracking studies, accompanied by illustrative examples using telemetry data. Expanding from this case study, we transition to a broader discussion were we provide overarching perspectives on tracking in open coastal ecosystems and offer recommendations to enhance future tracking studies in the Wadden Sea. The integration of telemetry methodologies aligns research and management with fish movement over multiple scales, improving our understanding of fish behaviors and contributing to more effective conservation strategies.

Qualitative detection of formaldehyde in challani fish obtained from selected fish markets of Nagaon, Assam, India

Preservatives are used to increase the shelf life of any product for a very long time, yet they are extremely detrimental to human health when used in food. The use of preservatives like formaldehyde by fishermen and fish merchants for prolonged preservation of fish during sales and transportation has recently become problematic and threat to human health. Therefore, the goal of the current investigation was to determine the presence of formaldehyde in the fish sold at fish markets in Nagaon, Assam. The present investigation indicates the contamination of fish with formaldehyde in the local fish markets of Nagaon district. The fish that show the presence of formaldehyde are imported (challani) and out of the whole fish sample collection (challani/imported), Labeo rohita, Catla catla indicates the highest positive result, with 35.96% and 48.44% respectively from the 114 Labeo rohita to 64 Catla catla samples. Additionally, the results for Ompok pabda, Pangasius pangasius, Hilsa ilisha, and Piaractus brachypomus are all positive, with Hilsa ilisha showing a positive result of 100% from their whole sample collection. However, the local fish like Labeo gonius, Cirrhinus reba, Ctenopharyngodon idella, Cirrhinus mrigala, and Hypophthalmicthys nobilis fish species have shown 100% negative results for formalin detection, indicating that their samples are formalin-free. Since formaldehyde is harmful to human health, better methods and techniques should be adopted for the preservation of fish for commerce and storage. Strict regulations should be put in place to limit the use of these hazardous chemical substances.

Accumulation of potentially toxic elements in fourfinger threadfin (Eleutheronema tetradactylum) and black pomfret (Parastromateus niger) from Selangor, Malaysia.

The accumulation of potentially toxic elements (PTEs) has raised public awareness due to harmful contamination to both human and marine creatures. This study was designed to determine the concentration of copper (Cu), zinc (Zn), cadmium (Cd), and nickel (Ni) in the intestine, kidney, muscle, gill, and liver tissues of local commercial edible fish, fourfinger threadfin (Eleutheronema tetradactylum), and black pomfret (Parastromateus niger) collected from Morib (M) and Kuala Selangor (KS). Among the studied PTEs, Cu and Zn were essential elements to regulate body metabolism with certain dosages required while Cd and Ni were considered as non-essential elements that posed chronic and carcinogenic risk. The concentration of PTEs in fish tissue samples was analyzed using flame atomic absorption spectrometry (F-AAS). By comparing the concentration of PTEs in fish tissues as a bioindicator, the environmental risk of Morib was more serious than Kuala Selangor because both fish species collected from Morib resulted in a higher PTEs concentration. For an average 62kg adult with a fish ingestion rate (FIR) of 0.16kg/person/day in Malaysia, the estimated weekly intake (EWI) of Cd from the consumption of E. tetradactylum (M: 0.0135mg/kg; KS: 0.0134mg/kg) and P. niger (M: 0.0140mg/kg; KS: 0.0132mg/kg) had exceeded the provisional tolerable weekly intake (Cd: 0.007mg/kg) established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and oral reference dose (ORD) values of Cd (0.001mg/kg/day) as provided by the United States Environmental Protection Agency (USEPA) regional screening level, thus it posed chronic risks for daily basis consumption. Besides, the value of the carcinogenic risk of Cd (0.7-3 to 0.8-3) and Ni (0.5-3 to 0.6-3) were in between the acceptable range (10-6 to 10-4) of the health index that indicates a relatively low possibility cancer occurrence to the consumers in both Morib and Kuala Selangor. This study recommended FIR to be 0.80kg/person/day to reduce the possibility of posing chronic and carcinogenic risks while at the same time obtaining the essential nutrients from the fish.

Development of a quantitative colorimetric LAMP assay for fast and targeted molecular detection of the invasive lionfish Pterois miles from environmental DNA

The Mediterranean basin has faced an increased influx of invasive species since the Suez Canal expansion in 2015. The invasive lionfish species, Pterois miles, has rapidly established new populations in the Eastern Mediterranean Sea, impacting local fish biodiversity. Here, we have developed a new, fast (&amp;lt; 35 min) molecular approach to detect and quantify P. miles environmental DNA (eDNA) in combination with a portable device for field-based analysis. Using a species-specific real-time colorimetric loop-mediated isothermal amplification (qcLAMP) for the cytochrome oxidase subunit 1 (COI) gene, we demonstrate a high sensitivity with a limit of detection of 0.002 ng DNA per reaction, equivalent to only 50 copies of the COI gene. The assay is specific to the target in the presence of closely related and co-occurring species, and it is quantitative over five orders of magnitude. We validated the assay using aquarium water samples and further demonstrated its utility on natural eDNA samples collected from locations around the island of Crete where P. miles had been sighted. P. miles was indeed detected in three out of nine locations, two nature reserves and a closed bay. Lack of detection in the remaining locations suggests that populations are still at a low density. We also demonstrate the feasibility of P. miles eDNA qualitative detection directly from the filter used to collect eDNA-containing particles, completely omitting DNA extraction. Overall, we present a new approach for fast and targeted eDNA quantification. The developed LAMP assay together, with the quantitative real-time colorimetric detection approach, open new possibilities for monitoring invasive P. miles in the field.

Fishing damage to cloud sponges may lead to losses in associated fish communities in Pacific Canada

Glass sponge gardens are important biogenic habitats that support fish communities in Pacific Canada. However, glass sponges (class Hexactinellida) are delicate and susceptible to damage from fishing gear such as downriggers. In this study we document changes in a fish community before –and after damage from a presumed fishing event that resulted in a reduction of 58.9% of the available sponge habitat in a small cloud sponge garden in British Columbia. This habitat loss coincided with a decline of 76.9% of the relative abundance of rockfish, an economically important group of fishes, at the garden. This decline was particularly pronounced in small size classes with the disappearance of juvenile rockfish after the sponge loss. Although based on a single site, this is the first documentation of how anthropogenic damage in a sponge aggregation may impact the associated fish community. Damage from fishing gear is likely most pronounced in small sponge aggregations, like nearshore gardens, where a single event may result in a disproportionately large loss of available fish habitat. Slow regrowth of sponges suggests the habitat availability may be permanently altered at these sites and can coincide with shifts in the localized fish community that may be long lasting on a local scale. Currently sponge gardens do not have any direct spatial protections in the Pacific Northwest, and this work highlights the importance of considering them in future protection initiatives.

Diversity of Fish and Decapod Fry in the Coastal Zone of Amvrakikos Gulf

Amvrakikos Gulf and its surrounding coastal lagoons are of primary importance for the local biodiversity and fishing activities. Fish species inhabited the coastal lagoons based on the seasonal ongoing migration movements of fry and adult fish individuals from the sea towards the lagoons. Information on the early stages of fish and decapod species in the Amvrakikos Gulf is limited only to the planktonic ontogenetic stages and reproduction biology, respectively. The aim of this study was to describe the spatial distribution of fry from commercially important fish and decapod species in the coastal zone of Amvrakikos Gulf. The seasonal appearance of the early stage of the most commercially important fish species caught in the coastal zone of the gulf ranged from one to four seasons, depending on the species. Individuals of all ontogenetic stages (fry, juveniles, and adults) were reported for several species (A. boyeri, A. fasciatus, S. abaster, S. tyfle, and B. ocellaris), indicating that these species may be regarded as residents in the coastal zone, providing habitats for their entire life cycle. The average relative abundance of the species/genera exhibited no differences compared to other Greek brackish waters. The species composition in the Amvrakikos Gulf at 10 cm and above was in agreement with the transitional nature of the area, with permanent and occasional species present. The present study emphasizes the importance of the coastal zone as a nursery habitat for commercially important species.

АНАЛИЗ РЫНКА РЫБНОГО СЫРЬЯ г. КЕМЕРОВО

The purpose of the study is to conduct marketing research of the fish products market in order to determine the needs and preferences of residents of Kemerovo, as well as assess the possibilities of using fish products from local producers of appropriate quality. Objectives: to determine the level of consumption of fish products in the city of Kemerovo; to identify the main producers and the structure of the assortment of the consumer market; to consider the sales volumes of fish products on the market of the city of Kemerovo. To study the analysis of the state of the raw fish market in Kemerovo, eight retail outlets were selec¬ted. Statistical reporting data characterizing the state of the fishery market was collected and analyzed. The conducted review of the fish products market makes it possible to determine the level of consumer preferences of Kemerovo residents from the supply position, to identify the main features of the market, problems and potential for further growth. Analysis of the data obtained shows that the raw fish market in Kemerovo is represented by products from both local producers and fish processors from other regions and countries. More than 55 % of the range of fish products comes from foreign producers and fish pro¬ducts from Russian regions. One of the main problems is the low share of local production in the regional market. To achieve positive results in increasing local fish production, state support is required in the form of subsidies and benefits for local producers of fish and fish products. This will stimulate production growth and ensure affordable prices for consumers with high quality products and reduce dependence on imports. Attracting investors to expand and modernize regional fish farming and production, improving product quality, organizing the production of high-quality fish products that meet quality and safety standards – all this will help increase consumer confidence and create loyalty to local brands.

STRATEGI PENGEMBANGAN EKOWISATA BUKIT BATU, DUSUN SUNGAI LUAR, DESA TIWINGAN BARU, KECAMATAN ARANIO, KABUPATEN BANJAR, PROVINSI KALIMANTAN SELATAN

This research aims to determine what strategies can be taken in managing Bukit Batu Ecotourism. This is because Bukit Batu Ecotourism has considerable potential, including biotic potential such as flora and fauna as well as abiotic potential such as mountains, hills, rivers, forests and lakes which of course have an attraction for tourists. The analytical method used in this research is a qualitative descriptive method. Where this research activity was carried out in natural and uncontrived object conditions, then the data obtained was analyzed using SWOT analysis. the SO strategy in order of priority which is described as follows: (1) Create tourist attractions and attractions that display ecological potential and diversity of flora and fauna such asaviary (giant bird cages), a mini zoo, an aquarium that accommodates local fish species and a miniature Borneo rainforest featuring endemic plant species. (2) Make a viewing tower to enjoy the beautylandscape mountains and lakes as a whole. (3) Empowering the surrounding community in managing Ecotourism such as retribution officers, cleaning officers and security officers. (4) Make plans for the development of facilities and infrastructure based on the most important priorities, such as telecommunication and internet signal booster towers, repair of roads that are still damaged and street lighting. (5) Increase safety warning boards. And (6) Empowerment of BUMDES (Village-Owned Enterprises) with clear work contracts so that they can have an impact on increasing the economy of the surrounding community, such as providing boat rental services, tour guides, bicycle/tent rental and selling souvenirs.

Restoration of an Indigenous aquaculture system can increase reef fish density and fisheries harvest in Hawai‘i

AbstractWhile aquaculture is increasingly considered a globally important source of protein, growing fish for human consumption is not new. Indigenous aquaculture systems, such as loko i‘a (fishponds), were successfully implemented in ancient Hawai‘i and represent a technological advancement designed to sustain a growing human population while maintaining—instead of supplanting—natural ecosystem function in the process of increasing food availability. Biocultural restoration efforts in Hawai‘i, aimed at revitalizing Indigenous stewardship, have included restoration of loko i‘a to sustainably increase the availability of local seafood. While it is clear from historical accounts that loko i‘a can augment fish within estuaries, their role as a nursery ground that supplements surrounding fish populations and fisheries harvest (i.e., providing spillover) remains unstudied in the current literature. This study aimed to test the extent to which loko i‘a restoration can supplement fish populations and fisheries harvest both inside the loko i‘a and in the surrounding waters. A food web model was constructed representing nutrients, phytoplankton, fish, and fisheries in three distinct habitats. The model, set in Kāne‘ohe Bay, O‘ahu, Hawai‘i, revealed that there were interactive effects of the area under loko i‘a management, bay fishing effort, and fish dispersal rates on fish density and fisheries harvest. We found that increasing the area under loko i‘a management not only increased loko i‘a fish density and fisheries harvest but also created the potential to supplement bay fish populations and fisheries harvest under certain scenarios. We also identified a trade‐off whereby at high fish dispersal rates, a larger area under loko i‘a management provided maximal benefits to the bay fish population and fisheries harvest, while at low fish dispersal rates, a smaller area under loko i‘a management was more beneficial to bay fish populations and harvest. As expected, loko i‘a also created a surplus of fish within the pond. Our results support the idea that restoration of Indigenous aquaculture systems can positively impact conservation efforts and food security by increasing local fish availability, through both direct production and supplementation of surrounding fish stocks.

Catalyzing Conservation: An Analysis of Fish Stock Dynamics in a Marine Protected Area before and after Artificial Reef Deployment

The marine ecosystem’s balance is crucial for sustaining biodiversity and supporting fisheries. Marine protected areas have been increasingly used to enhance marine habitats, yet their impact on fish populations remains a topic of debate. This study focuses on a marine protected area in Kitros, Pieria, in Greece, where an artificial reef was constructed, to understand its influence on coastal fish populations. The objectives were to investigate the changes in fish biomass and abundance, comparing the data from periods before and after the construction of an artificial reef. This research compares the data between 2007 and 2008 with the data between 2016 and 2017, collected with bottom trawl surveys strategically executed prior to and after the artificial reef’s installation. Fish species captured were identified, with their lengths and masses measured. The findings indicate an increase in the biomass and abundance of certain fish species after artificial reef deployment, notably the commercially significant Mullus barbatus and Pagellus erythrinus. The artificial reef in Kitros, Pieria, with its surrounding marine protected area appears to have had a positive impact on the local fish populations over the years, suggesting that it can contribute to marine conservation and fishery enhancement. These results underscore the potential of artificial reefs as tools for marine ecosystem management, offering insights for policymakers and environmentalists into coastal resource management.