An experimental evaluation of the effect of escape gaps on the quantity, diversity, and size of fish caught in traps in Montserrat

Coral reef fisheries are vital to the livelihoods of millions of people worldwide but are challenging to manage due to the high diversity of fish species that are harvested and the multiple types of fishing gear that are used. Fish traps are a commonly used gear in reef fisheries in the Caribbean and other regions, but they have poor selectivity and frequently capture juvenile fish, impacting the sustainability of the fishery. One option for managing trap fisheries is the addition of escape gaps, which allow small fish to escape. We compared catches of traps with and without two 2.5 cm (1 inch) escape gaps on the Caribbean island of Montserrat. No significant differences were found in the mean fish length, total fish biomass, number of fish, fish species richness, and Shannon diversity index between hauls of the two trap designs, though traps with escape gaps did catch larger proportions of wider-bodied fish and smaller proportions of narrow-bodied fish. Furthermore, traps with gaps caught a smaller proportion of small-sized fish and fewer immature fish (though differences were not statistically significant). Linear mixed effect models predict that soak time (the length of time between trap hauls) increases the mean catch length, total catch biomass and total number of species in the catch. The relatively modest evidence for the effect of the gaps on catch may be explained by the long soak times used, which could have allowed most smaller-sized fish to escape or be consumed by larger individuals before hauling in both traps with and without escape gaps. Despite the small differences detected in this study, escape gaps may still offer one of the best options for improving sustainability of catches from fish traps, but larger escape gaps should be tested with varying soak times to determine optimum escape gap size.

The growth pattern and condition factors of three spot gourami Trichopodus trichopterus (Pallas, 1770) from the Lempake Dam, East Kalimantan

The growth pattern and condition factors of three spots gourami Trichopodus trichopterus (Pallas, 1770) from Lempake Dam, East Kalimantan, are not yet informed. These studies aimed to investigate fishes' length and body weight, sex ratio, length-bodyweight relationships, growth patterns, and condition factors. The collection of fish sampling was carried out monthly from February to May 2020. A total of 912 individual samples of sepat rawa fish were caught by 15 fish traps using a purposive sampling method at three stations. This research showed that the total length of the fishes analyzed ranged from 31.68 to 103.53 mm, while body weight ranged from 1.12 to 7.22 g. The sex ratio in males and females was 1:1.19. The regression model of the length-body weight relationships calculated was W=3x10-5L2.861 for total samples, W=5x10-5L2.710 for males, and W=2x10-5L2.977 for females. The length-body weight was obtained strong relationships in all samples and sexes, with the regression coefficient (r) ranging from 0.965 to 0.977. An isometric growth pattern and the growth coefficient “b”=2.977 was observed in females, while a negative allometric growth pattern in males and both sexes, with the growth coefficient “b”= 2.710 and “b”=2.861. The values of relative condition factor (Kn) observed for females were ranged from 1.472 to 1.555 and for males ranged from 1.024 to 1.082. The growth pattern and relative condition factor of three spot gourami in the Lempake Dam were affected by the number of fishes in gonad mature condition and body shape.

Diversity of Fishing Equipment for Fishermen in Gunung Kijang District, Bintan Regency

The increase in fishery production in Gunung Kijang District cannot be separated from fishing activities. The use of fishing gear that has the potential to damage the environment is assumed to be caused by public ignorance about the dangers of these tools. However, information about the diversity of types of fishing gear used by fishermen in Gunung Kijang District is still scarce. The purpose of the preparation of this scientific article is to provide information about the types of fishing gear used by the community in Gunung Kijang District, Bintan Regency. The preparation of this scientific article was carried out in April 2021 in Gunung Kijang District using a descriptive analysis based on a literature review using secondary data as a source of information. The fishing gear used by Gunung Kijang fishermen include mackerel nets, tuna, stingrays, corals, crabs, floating nets, motor boat charts, fish traps, crab traps, oval crab traps, fishing rods, longline fishing rods, spears, fish guns.

Stone-Walled Fish traps of Australia and New Guinea as Expressions of Enhanced Sociality

Fishing was and remains an important subsistence activity of many coastal and inland Indigenous peoples of Australia and New Guinea. The range of ethnographically known fishing methods used to obtain freshwater and marine fishes is similar across the two regions. This ethnographic picture of diversity and complexity is not matched archaeologically, where stone-walled fish traps dominate. Archaeological research on stone-walled fish traps has focused on technical dimensions (e.g., mapping, classification, and dating) and social dimensions (e.g., gender, social complexity, and social organization). Stone-walled fish traps can transform the social and ecological landscape and, in an archaeological context, provide an opportunity to explore decision making and the sociocultural changes associated with the installation of these fixed-in-place facilities. Relevant social organizational changes with potential material correlates amenable to archaeological research include the restructuring of residential sites; interregional gatherings and exchange relationships; aquatic resource enhancement and regularization; and ownership and control of facilities and resources, including territorial partitioning of land- and seascapes.

The Spirit Of Water

This book describes a research project begun by the author in 2015 and co-authored by the chiefs of the KhoiSan peoples living in the Nelson Mandela Bay Municipality, South Africa, aided by staff and students at Nelson Mandela University. The scope of the project was to investigate methods and procedures that could help re-establish the link between the Indigenous communities and their ‘forgotten’ heritage sites due to the colonial segregations. Making use of a participatory and interdisciplinary method we explored the tangible and intangible heritage of the Eastern Cape province, with particular attention to the remains of precolonial fish traps located along the shoreline. Included also are important testimonies from the KhoiSan chiefs who, alongside the author, led the project.

Applicability justification and structural schemes of live fish containers for fish seining, transportation and releasing

Purpose: substantiation and development of structural schemes of live fish containers for fish seining, transporting and releasing, adapted for use in fish traps, which are part of the hydraulic facilities of fish-breeding and fish-breeding-reclamation complexes. Materials and Methods. The experimental base for substantiating the applicability of developing designs for live fish containers for fish traps is made up of survey data of pond and basin fish breeding complexes. The methodological basis for the containers design was formed by technologies and methods of the design theory of new technology. Results. It is shown that the technologies used for seining, transportation and releasing fish stock grown in ponds using permeable (perforated) containers have a negative impact on the physiological state of underyearlings and yearlings of fish, which justifies the applicability of using live fish containers. The requirements for the structures of live fish containers used in fish-catching structures of fish-breeding complexes have been determined. Two competing design schemes of impervious containers with a pneumatic fish release system and a fish outlet port have been proposed. Structurally, containers are made in the form of a prismatic container with impervious sides and a flat bottom. In a container with a pneumatic system, a perforated platform movable by it is provided, which allow ensuring the presence of fish in it and their release into the reservoir depending on its vertical location in the container inner cavity. In the hatch port structure in the bottom of the container, a hatch device is provided with the possibility of moving it to the open and closed positions, the regulation of which allows the fish accumulation, presence and release into the reservoir. Conclusion. As a result of the research carried out, the applicability of using live fish containers was substantiated and two options for their design were proposed.

Hydraulic structures and devices works providing a non-contact technology for fish release, seining and transfer of fish cultivated in fish breeding complexes

Purpose: development of an outlet and fishing structures works, providing for fish release from fish-breeding reservoirs, their seining, transfer and inlet into feeding reservoirs using non-contact technology. Materials and methods. The basis of the research was the data of studying the applied technologies, structures and means of intra-complex fish transfer between fish-breeding facilities and during stocking of reservoirs. Results. When fish are cultivated in fish breeding complexes, it is necessary to transfer them from nursery reservoirs to wild or stocked objects for fish farming and their biological reclamation. When providing fish-breeding activities, fish are released from nursery reservoirs by means of water outlets, seined in fish-traps, transfered and released into a water body. The applied complexes of structures provide for a physical effect on fish, which leads to injury to a part of the fish planting material. To exclude this, design solutions for fish outlet and fish processing facilities and live fish containers operating in the complex, providing the release, seining, transfer and inlet of fish using non-contact technology with technical means are proposed. Conclusions. A layout and design solution for a unit of linearly spaced interconnected fish-breeding structures, including a bottom fish outlet and a container fish trap, providing, when they work together, release and seining fish fry cultivated in fish-breeding reservoirs, is proposed. The applied and proposed technological schemes of functioning of the complex of structures, devices and means for fish release from fish-breeding basins, their catching, transfer and admission to the feeding reservoir are presented. A constructive solution for a live fish container for non-contact fishing, movement and admission of fish stocking material into the reservoir to be stocked is proposed.

Bioecology of Manggabai Fish (Glossogobius giuris) in Limboto Lake

The purpose of this study was to determine the relationship between the length and weight of Manggabai fish (Glossogobius giuris) and to know the relationship between the presence of Manggabai fish (Glossogobius giuris) and water quality in Limboto Lake. This research was conducted in February 2019, located in the waters of Lake Limboto, Gorontalo Province. The method used in determining the location of sampling is Purposive Sampling. Fish sampling is determined by considering fishing locations, litoral areas, the presence of residential areas, agricultural and plantation areas, the existence of floating net cages and in the middle of the lake. The study was conducted at 20 observation stations using fish traps in the form of bamboo and used motorcycle tires that have been modified and become traditional fishing gear. The results showed that the physical and chemical parameters in Lake Limboto and showed temperature values ​​ranged from 29.77 to 31.630C, dissolved oxygen levels ranged from 2.1 to 5.48 ppm, pH ranged from 7.09 to 8.94, TDS ranging from 0.251 to 0.369, Nitrite Levels 0.04-0.08 ppm, Nitrate Levels 1.2-4.7 ppm, BOD ranges from 2.5-57 ppm and phosphate levels 0.1-1.14 ppm. The relationship between length and body weight of fish are allometric, where W = 0.8769 L10,023 and constant b (10,023)> 3.