Mean Fish Biomass Research Articles

Examining the effectiveness of bored pile coral for coral rehabilitation

Abstract. Putri NP, Muharam MR, Ritonga A, Ruswanti CD, Arthen D, Munasik. 2024. Examining the effectiveness of bored pile coral for coral rehabilitation. Biodiversitas 25: 153-161. Semut Island is located in Kiabu Village, Anambas Islands, Riau, Indonesia, and has suffered significant damage to its coral cover due to blast fishing. To address this issue, Anambas Foundation initiated a coral reef rehabilitation on Semut Island using a customized artificial reef called Bored Pile Coral (BPC), a cylindrical structure made of concrete hammered into the seabed. This research aims to examine the effectiveness of BPC by monitoring its performance. Therefore, from February 2022 to January 2023, 1,500 BPCs were deployed and attached with corals covering an area of 170 m2. We quantified five ecological indicators, i.e., coral cover, survival rate, recruitment, growth rates, and fish biomass. Results showed an increase in coral cover from 3.8% to 8%. The survival rate was 64%, and the mean monthly growth rates varied among three genera: Pocillopora sp. (0.235±0.02 month-1), Acropora sp. (0.22±0.03 month-1) and Porites sp. (0.08±0.02 month-1). The monthly mean fish biomass data showed the biomass was 427,25 Kg/Ha and increased 3,9 times since the beginning of the research. BPC's structure has been proven to act as stable media for hard corals, although the modification may be necessary to enhance structural complexity and suitability for carnivorous fish habitats.

Hydroacoustic survey on fish spatial distribution in the early impoundment stage of Yuwanghe Reservoir in southwest China

Understanding the fish community structure and spatial distribution characteristics is essential for appropriate reservoir fishery management, especially in the early impoundment stage of the reservoir, which could help in obtaining basic data and performing artificial adjustments to biological communities. On the basis of this concept, we conducted a survey of the fish community and distribution at the newly constructed reservoir in southwest China by using a combination of methods, including hydroacoustic survey and fish sampling. Fish sampling showed a single fish community structure (six species belonging to four families) assembled in the reservoir, and the dominant species was Pseudorasbora parva which accounted for 98.79% of the fish population. In the hydroacoustic survey, the average fish density was 318.7 ± 256.1 individuals/1,000 m2. Irregular distribution of the fish was observed in the horizontal direction. The fish densities in the head area, middle area, and tail area of the reservoir were 168.5 ± 60.1, 306.8 ± 124.7, and 696.4 ± 288.9 individuals/1,000 m2, respectively, which showed a trend of increase in fish density with an increase in distance from the dam. More than 97.3% of the fish in the vertical direction were distributed in the water layer of depth 0 to 12 m. The average total length of fish was 75.4 mm, and the mean fish biomass in the reservoir was approximately 984.8 g/1,000 m2. According to Pearson correlation analysis, the main factors affecting the spatial distribution of fish were water depth, water temperature, dissolved oxygen, total nitrogen, and plankton density. Our results suggested that the fish community structure should be adjusted by releasing native carnivorous fish to control the abundance of small fish. Moreover, filter-feeding fish such as silver carp and bighead carp should be released in the reservoir to control the plankton community; this will enable the maintenance of the reservoir ecosystem in a healthy state while increasing the economic benefits to the local area.

Long-term mean biomass and dominant fish species in the bottom and near-bottom biotopes of Peter the Great Bay

Biomass and species composition of demersal fish in the bottom biotopes of Peter the Great Bay (Japan Sea) are considered on the data of 2428 trawl catches in 36 surveys conducted by Pacific Res. Inst. of Fisheries and Oceanography (TINRO) in 1978–2009. The most common 20 species are ranked, as the basis of ichthyocenoses, by areas of the bay. The long-term mean total biomass of fish in the bay is estimated as 75,500 t. Arabesque greenling Pleurogrammus azonus, japanese flounder Pseudopleuronectes yokohamae and saffron cod Eleginus gracilis are distinguished by the highest mean biomass. Mean density of fish distribution varied from 6.2 to 19.4 t/km2. It was the highest in the middle Ussuri Bay (13.95 t/km2; mean fish biomass in the area 18,230 t) and in the estuarine areas. Besides, the data on long-term mean biomass of benthos collected in the same trawl surveys and zooplankton sampled in 117 plankton surveys in 1988–2013 are presented.

Evaluating the efficacy of small‐scale marine protected areas for preserving reef health: A case study applying emerging monitoring technology

Abstract Marine protected areas (MPAs) are widely used as management tools to conserve species and ecosystems at risk from human impact. Coastal managers often focus MPA designation on biogenic reef environments due to their value and sensitivity to damage. However, difficulties in enforcement and a lack of capacity to adequately monitor MPAs often make it hard for managers to assess the effectiveness of MPAs, particularly in under‐resourced, low‐income coastal countries. Reef community data were collected at three long‐term managed reserves within the Western Visayas region of the central Philippines in order to assess the state of reef community structure inside and outside of these small‐scale locally managed MPAs. In addition, 3D structural data were captured using recently developed 'Structure from Motion' photogrammetry techniques, demonstrating how multiple quantitative metrics of physical structural complexity and health can be recorded in such analyses. These community‐run MPAs were shown to be effective even when small (10–20 ha). Mean fish biomass density was five times greater within present‐day protected sites, alongside significantly increased levels of fish diversity, richness, and size. No significant structural differences were observed inside and outside of MPAs; however, average reef rugosity, height, and roughness were significantly higher in unfished reefs compared to blast‐fished reefs. Reef substrate complexity, coral composition, and level of management, were also shown to structure fish community assemblages, with the link between reef structure and fish richness/abundance disrupted outside of MPAs. The Structure from Motion technique allows a greater range of quantitative morphometrics to be assessed than traditional methods and at relatively low cost. The technique is rapid, non‐destructive and can be archived, increasing the value of data for managers wishing to quantify reef health and efficiently monitor benthic changes through time. We discuss both the limitations and benefits of this technology's future use.

Marine megafauna niche coexistence and hotspot areas in a temperate ecosystem

In the last few decades, there has been a remarkable development of niche models to help understand the ecological response of species to current rapid environmental changes. In the present study, we applied niche modelling to the megafauna community of shelf waters of the northwestern (NW) and northern Iberian Peninsula in order to analyse the coexistence of different species taking into consideration their niche preferences. The Spanish Institute of Oceanography conducts the PELACUS multidisciplinary survey annually to assess pelagic fish stocks and collect information on the status of other ecosystem components, such as oceanographic conditions, phytoplankton, zooplankton and marine megafauna. Using data collected from these surveys, we developed niche models for 14 marine megafauna taxa (3 cetaceans, 10 seabirds and 1 fish) incorporating multi-trophic ecological descriptors collected simultaneously during the surveys alongside the more commonly used oceanographic variables (e.g. chlorophyll a and sea surface temperature). Megafauna niche models were developed by pooling observations from 2007 to 2013 and were found to be driven by mean fish biomass and its variability, in addition to sea surface temperature. Hierarchical clustering identified four distinct megafauna assemblages, the first comprising wide-ranging species and the other three associated with shelf-slope waters in Galicia, coastal/shelf waters in Galicia, and the eastern Cantabrian Sea, respectively. Community-level hotspot areas were found in shelf and shelf-break sectors of Galicia, along with small diversity spots scattered throughout the Cantabrian coastal area. Our results showed that synoptically collected survey-based ecological descriptors, especially acoustic-based preyscapes, were among the most important variables explaining megafauna niche preference. These findings highlight the advantage of using integrated ecosystem surveys to collect simultaneous information on a suite of ecosystem components for spatial assessments.

Ecological Changes in the Coral Reef Communities of Indonesia's Bali Barat National Park, 2011–2016

The coral reefs of Bali Barat National Park, one of Indonesia’s oldest marine protected areas, are known for their high biodiversity and excellent sport diving; however, stressors such as destructive fishing practices, elevated water temperatures, damage from anchors and careless visitors have been observed on these reefs for decades. The purpose of this study was to document and quantify changes in the fish and stony coral community structure of reefs within and outside the boundaries of Bali Barat National Park from 2011 to 2016, including its most popular dive site, Menjangan Island. The results provide further knowledge about the reefs of NW Bali and the efficacy of current management practices, and they will inform management decisions for locally managed reef stewardship programs. Between 2011 and 2016 the reefs of NW Bali lost 44.4% of their living coral cover, declining from 36% to 20% overall cover. Mortality was principally attributed to thermal bleaching caused by persistently high sea temperatures, which peaked in January 2016 at 32.2°C, coinciding with the third documented global bleaching event. Approximately one third of all stony corals were found to be bleached or recently dead. Despite the decline in coral cover, stony coral genus richness remained unchanged, with 56 genera recorded in both years, representing a combined total of 59 distinct genera. Mean fish biomass at Menjangan Island increased, with herbivorous fish biomass quadrupling, presumably due to decreased fishing effort at the island. The abundance of fish at all sites—both inside and outside the park—more than doubled, indicating a predominance of small fish at sites where fish biomass did not correspondingly rise. Crown-of-thorns starfish (Acanthaster planci), not observed on transects in 2011, were found in 2016 in areas of relatively high disturbance from marine recreation and possible eutrophication from shrimp farm effluent and mainland runoff. Patterns of coral cover and damage, fish abundance and biomass, and lost fishing gear suggest that management activities inside and outside the park have reduced ecological damage. Local community conservation groups are practicing one or more of the following at Menjangan Island and in some of the locally managed conservation areas: installing moorings, removing coral predators (crown-of-thorns starfish and Drupella snails), reducing fishing pressure, securing live coral fragments back onto the reef and planting mangroves. These nature groups are raising community awareness about the importance of NW Bali’s marine ecology to their economic and cultural wellbeing.

Fish production in estuaries of Primorye

Production of fish communities in 15 different-types estuaries was assessed based on the data collected as a result of 90 surveys (860 seine stations) conducted in Primorye in 2002–2015. The main contribution to production was made by semi-anadromous species (the so-iuy mullet Liza haematocheilus, Far Eastern redfins Tribolodon spp., and Japanese smelt Hypomesus nipponensis, etc.). In both external (EPext) and internal (EPint) polyhaline estuaries (EP) a substantial portion of the production was provided by resident marine species (mainly by the saffron cod Eleginus gracilis, Far Eastern smooth flounder Liopsetta pinnifasciata, and tidepool gunnel Pholis nebulosa) and southern immigrants (flathead grey mullet Mugil cephalus, dotted gizzard shad Konosirus punctatus, Japanese halfbeak Hyporhamphus sajori, and Pacific needlefish Strongylura anastomella). In mesohaline (EM) and oligohaline (EO) estuaries, the proportion of marine residents and southern immigrants was reduced to a minimum, while that of freshwater species (bighead gudgeon Gobio macrocephalus, Prussian carp Carassius gibelio, minnow Phoxinus spp., Amur bitterling Rhodeus sericeus, spiny bitterlings Acanthorhodeus spp., etc.) substantially added to the production of semi-anadromous fish. The mean fish biomass for the vegetation season varied in the 143–1463 mgC/m2 range; the mean annual production was 174–4267 mgC/m2 and the mean P/B ratio was 0.2–3.2. In 2007, the high annual production in the Artemovka River estuary, 9356 mgC/m2, was formed by the juvenile so-iuy mullet of the strong yearclass that hatched in 2006. The lowest mean production and P/B values were typical mainly for the water bodies with a salinity more often close to that of the barrier zones (5–8‰ for α-horohalinicum and 22–26‰ for β-horohalinicum), i.e., for EM and EPext. This relationship is explained by the features of the osmotic regulation in fish of various origins and its ontogenetic variations. In particularly, the salinity in EM is more frequently close to the critical salinity (5–8‰, α-horohalinicum); thus, the proportion of juveniles of most of the species in the catches decreases (as their resistance to salinity variations is lower). This results in higher mean values of the specific and absolute production of fish communities in EPint and EO as compared to those in EM. The conclusion was made that the estimates of fish production in the estuaries of Primorye are similar to those in the well-studied estuaries of the temperate, subtropical, and tropical zones. Moreover, they are comparable to the fish production estimates for mesotrophic and eutrophic lakes in northwestern Russia, substantially lower than those for large lowland rivers, and higher than those for small rivers. The fish production in seas, including the Japan/East Sea (0.20 gC/m2) and, particularly, Peter the Great Bay (0.28 gC/m2), is mostly lower than that in Primorye estuaries.

Production of fish in the estuaries of Primorye

Production of fish communities is evaluated for 15 types of estuaries in Primorye on the data collected in 80 surveys (860 seine stations) conducted in 2002-2015. The bulk of the production in all cases is formed by semi-anadromous species ( Liza haematocheilus , Tribolodon spp., Hypomesus nipponensis and others). In polyhaline estuaries ( EP ), a significant part of the production is formed by resident marine species (mainly by Eleginus gracilis , Liopsetta pinnifasciata , Pholis nebulosa ) and southern migrants ( Mugil cephalus , Konosirus punctatus , Hyporhamphus sajori , Strongylura anastomella ). In mesohaline ( EM ) and oligohaline ( EO ) estuaries, the portions of marine residents and southern migrants are minimal, but the portion of freshwater species ( Gobio macrocephalus , Carassius gibelio , Phoxinus spp., Rhodeus sericeus , Acanthorhodeus spp., etc.) is heightened. Seasonal dynamics of the production is distinguished by the maximum in July-September. Mean fish biomass in May-October (vegetation season) varies in the range 143-1463 mgС/m 2 , mean annual production - from 174 to 4267 mgС/m 2 , and mean P/B -ratio - from 0.2 to 3.2. Previously (in 2007) much higher annual production was registered in the Artemovka River estuary - 9356 mgС/m 2 , but such high value was formed only once by juveniles of L. haematocheilus belonged to highly abundant year-class hatched in 2006. Both production and P/B are the lowest in the waterbodies with salinity close to the barrier values (5-8 ‰ for a - horohalinicum and 22-26 ‰ for b - horohalinicum) that is usual for the types EM and EP ; this lowering is caused by osmotic regulation for freshwater and marine fish, respectively, in particular their juveniles with low tolerance to salinity changes. That’s why EM estuaries have lower abundance of juveniles relative to adult fish and therefore the lower production. In general, patterns of fish production in the estuaries of Primorye are similar to production of well investigated estuaries in the moderate, subtropical and tropical zones. The values of fish production in the estuaries of Primorye are comparable with the production in mesotrophic and eutrophic lakes of north-western Russia; being significantly lower than the production in large floodplain rivers but higher than the production in small rivers. Fish production for seas, including Japan Sea (0.20 gС/m 2 ) or its northwestern part - Peter the Great Bay (0.28 gС/m 2 ), is significantly lower.

Fine-scale spatial association between baleen whales and forage fish in the Celtic Sea

Baleen whales can be regularly observed in the Celtic Sea; however, little is known about their local foraging behaviour. The study objective was to determine whether or not baleen whales selectively prey upon particular forage fish species or, on the contrary, is predation on the Celtic Sea plateau driven by random encounters between prey and predator? Concurrent sighting surveys for fin (Balaenoptera physalus), minke (Balaenoptera acutorostrata), and humpback (Megaptera novaeangliae) whales were carried out simultaneously from 2007 to 2013 during dedicated fisheries acoustic surveys assessing the abundance and distribution of forage fish. Probabilities of spatial overlap between baleen whales and forage fish were analysed and compared with the probability of a random encounter. For estimations of foraging threshold and prey selectivity, mean fish biomass and fish length were calculated when baleen whales and forage fish co-occurred. Whales were dominantly observed in areas with herring (Clupea harengus) and sprat (Sprattus sprattus), while areas with mackerel (Scomber scombrus) were not targeted. A prey detection range of up to 8 km was found, which enables baleen whales to track their prey to minimize search effort. Fish densities within the defined foraging distance ranged from 0.001 to 3 kg·m−2 and were correlated to total fish abundance. No prey size selectivity according to fish length was found. By linking baleen whale distribution to high-density herring and sprat areas, it was possible to identify the Celtic Sea as a prey hot spot for baleen whales during autumn.

Effects of volcanic ash deposits on four functional groups of a coral reef

The immediate effects of pyroclastic deposits (ash fall) on reef communities after volcanic eruptions on remote tropical islands have never been critically examined. This study discusses findings from an interdisciplinary research expedition to the island of Anatahan (Commonwealth of the Northern Mariana Islands), 4 months after its first recorded volcanic eruption. Deep ash completely obliterated any trace of reef communities off the northeastern shores of the island; however, reefs in other areas, although still blanketed with ash deposits, fared better. Mean fish biomass recorded around Anatahan after the eruption was 0.22 kg 100 m−2, a value three times lower than at Sarigan, the closest neighbor island. Similarly, average percent cover of live coral (7.9%), crustose coralline red algal (7.7%), and macroalgal (14.3%) populations was 2.3, 1.4, and 3.0 times lower than at Sarigan, respectively.

Comparison of fish community structure on artificial reefs deployed at different depths on turkish Aegean sea coast

Deployment depth of artificial reefs is one of the most important issue in planning stage and future success. Most of the studies aimed at determination of fish community around artificial reefs were conducted mainly 10-25m depths in Mediterranean and Aegean Sea. The goals of this study are determine and compare of fish community structure around artificial reefs which deployed 20, 30 and 40 m depths. Underwater visual census technique was used to determine fish species, number of individual and size estimation. There was no statistical difference (p>0.05) in mean fish biomass and number of individual between the depths. But mean species number was significantly greater on 20 m in comparison to 30 m and 40 m depths (p<0.05). Furthermore, calculated values of Jaccard and Bray-Curtis indexes showed low similarity (min. 3% - max. %37) between depths.

Gradients of abundance and biomass across reserve boundaries in six Mediterranean marine protected areas: Evidence of fish spillover?

Marine protected areas (MPAs) are considered as an effective tool in marine coastal management, and considered able to enhance local fisheries through adult fish spillover. Indirect evidence of fish spillover could be obtained by horizontal gradients in fish abundance. To address this question, the existence of gradients of fish abundance and biomass across marine reserve boundaries was assessed in six Mediterranean MPAs using underwater visual censuses performed at various distances from the core of the MPA, in integral reserve (IR), to buffer zone (BZ) and fished areas. A reserve effect was evidenced with higher values of fish species richness (×1.1), abundance (×1.3), and biomass (×4.7) recorded inside MPAs compared to adjacent fished areas. Linear correlations revealed significant negative gradients in mean fish biomass in all the reserves studied after the effect of habitat had been removed, whereas negative gradients in abundance were less conspicuous. Generalized additive models suggested two main patterns of biomass gradients, with a sharp decrease at the IR–BZ boundary or at the BZ–fished area boundary. It was estimated that fish spillover beneficial to local fisheries occurred mostly at a small spatial scale (100s of metres). The existence of regular patterns of negative fish biomass gradients from within MPAs to fished areas was consistent with the hypothesis of adult fish biomass spillover processes from marine reserves and could be considered as a general pattern in this Mediterranean region.

Distribution and biomass of an underfished vendace, Coregonus albula, population in a mesotrophic German reservoir

Abstract The distribution and overall biomass of an underfished vendace, Coregonus albula L., population in the mesotrophic Henne Reservoir (Germany) was studied using hydroacoustics and gill nets. Additionally, midwater trawling was carried out. Overall fish biomass, based on five hydroacoustic surveys (June to September 2002), ranged from 188 kg ha−1 in early August to 302 kg ha−1 in September 2002. The overall mean fish biomass was 256 kg ha−1 (±48 kg ha−1 SD). Biomass of fish smaller than 25 cm total length (mostly vendace) varied from 56 kg ha−1 in August to 99 kg ha−1 in September, with an overall mean fish biomass of 74 kg ha−1 (±17 kg ha−1 SD). The echograms showed temporal variation in fish distribution in Henne Reservoir. In June, fish were fairly evenly distributed over the whole reservoir but in September a dense aggregation of fish (mostly vendace) was found in the deeper water layers near the dam. The distribution of vendace stock, its impact on water quality and fisheries management, biomanipulation and effort for mass removal are discussed.

Effects of Artisanal Fishing on Caribbean Coral Reefs

Abstract: Although the impacts of industrial fishing are widely recognized, marine ecosystems are generally considered less threatened by artisanal fisheries. To determine how coral reef fish assemblages and benthic communities are affected by artisanal fishing, we studied six Caribbean islands on which fishing pressure ranged from virtually none in Bonaire, increasing through Saba, Puerto Rico, St Lucia, and Dominica, and reaching very high intensities in Jamaica. Using stationary‐point fish counts at 5 m and 15 m depth, we counted and estimated the lengths of all noncryptic, diurnal fish species within replicate 10‐m‐diameter areas. We estimated percent cover of coral and algae and determined reef structural complexity. From fish numbers and lengths we calculated mean fish biomass per count for the five most commercially important families. Groupers (Serranidae), snappers (Lutjanidae), parrotfish (Scaridae), and surgeonfish (Acanthuridae) showed order‐of‐magnitude differences in biomass among islands. Biomass fell as fishing pressure increased. Only grunts (Haemulidae) did not follow this pattern. Within families, larger‐bodied species decreased as fishing intensified. Coral cover and structural complexity were highest on little‐fished islands and lowest on those most fished. By contrast, algal cover was an order of magnitude higher in Jamaica than in Bonaire. These results suggest that following the Caribbean‐wide mass mortality of herbivorous sea urchins in 1983–1984 and consequent declines in grazing pressure on reefs, herbivorous fishes have not controlled algae overgrowing corals in heavily fished areas but have restricted growth in lightly fished areas. In summary, differences among islands in the structure of fish and benthic assemblages suggest that intensive artisanal fishing has transformed Caribbean reefs.

Land use, associated eel production, and abundance of fish and crayfish in streams in Waikato, New Zealand

The density and biomass of fish and crayfish, and the production of eels, was compared among streams in native forest, exotic forest, and pasture. Populations were estimated by multiple‐pass electroshocking at 11 sites in hill‐country streams in the Waikato region, North Island. Three sites were in native forest, four in exotic forest, and four in pasture. Length of stream sampled at each site was 46–94 m (41–246 m2 in area), and catchment areas up stream of the sites ranged from 0.44 to 2.01 km2. A total of 487 fish were caught. The species were longfinned and shortfinned eels, banded kokopu, Cran's and redfinned bullies, and common smelt. Eels were the most abundant fish in all three land‐use types, and shortfinned eels were more abundant at pastoral sites (mean density 1.11 fish m−2) than longfinned eels (mean density 0.129 fish m−2). Banded kokopu were present only at forested sites. Mean fish densities were greater at pastoral sites (1.55 fish m−2) than under either native forest (0.130 fish m−2) or exotic forest (0.229 fish m−2). Mean fish biomass was also greater at pastoral sites (89.7 g m−2) than under native forest (12.8 g m−2) or exotic forest (19.3 g m−2). Longfinned eels made a greater contribution to the fish biomass at all sites than did shortfinned eels. Densities of crayfish were high (0.46–5.40 crayfish m−2), but were not significantly different between land‐use types. Crayfish biomass ranged from 1.79 to 11.2 g m−2. Total eel production was greater at pastoral sites (mean 17.9 g m−2 year1) than at forest sites (mean 2.39 gm−2 year−1).

How far do prawns and fish move into mangroves? Distribution of juvenile banana prawns Penaeus merguiensis and fish in a tropical mangrove forest in northern Australia

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 131:115-124 (1996) - doi:10.3354/meps131115 How far do prawns and fish move into mangroves? Distribution of juvenile banana prawns Penaeusmerguiensis and fish in a tropical mangrove forest in northern Australia Vance DJ, Haywood MDE, Heales DS, Kenyon RA, Loneragan NR, Pendrey RC It is accepted that mangroves are important nursery areas for prawns and fish, including some of major commercial importance, but little is known about how these mobile animals use the mangrove forests. We recorded the distribution of juvenile banana prawns Penaeusmerguiensis and of fish in an intertidal mangrove forest adjacent to a small creek in northern Australia in November 1992 and in March 1993. Four discrete areas of the forest were enclosed with a 100 m long, 2 mm mesh stake net: 2 at the creek mangrove fringe and 2 at further distances into the mangroves. The mean distance of each sampling site inland from the creek mangrove fringe ranged from 13 to 59 m and the area of the sites ranged from 480 to 640 m2. Two mangrove communities, one dominated by the structurally complex Rhizophorastylosa, the other by the more open Ceriopstagal were sampled. A large size range of juvenile prawns and small fish moved at least 43 m into the mangroves at high tide, and the density of prawns near the creek mangrove fringe was inversely related to the maximum tide height. The highest density of juvenile P. merguiensis recorded in the mangroves in November was 18.3 prawns 100 m-2 and in March was 334.5 prawns 100 m-2. Mean fish density over all samples was 83.0 fish 100 m-2 and mean fish biomass was 3.9 g m-2; 55 species of fish were caught during the sampling. P.merguiensis showed no apparent preference for either of the 2 mangrove communities sampled; however, more fish (101 fish 100 m-2) and more fish species (26) were caught at the creek mangrove fringe site than at the other more inland sites; the lowest numbers of fish (27 fish m-2) and species (13) were caught at the inland site (Ceriops). On average, fish caught at the fringe site were also longer and heavier than fish caught at the other sites. By moving well into the mangrove forest, prawns and small fish are probably less vulnerable to predation by larger fish. Penaeid . Mangroves . Fish . Stake net . Distribution . Intertidal Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 131. Publication date: February 08, 1996 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1996 Inter-Research.

Mangrove fish-communities in tropical Queensland, Australia: Spatial and temporal patterns in densities, biomass and community structure

Regular daylight sampling over 13 mo (February 1985February 1986) in and adjacent to intertidal forested areas, in small creeks and over accreting mudbanks in the mainstream of a small mangrove-lined estuary in tropical northeastern Queensland, Australia, yielded 112 481 fish from 128 species and 43 families. Species of the families Engraulidae, Ambassidae, Leiognathidae, Clupeidae and Atherinidae were numerically dominant in the community. The same species, with the addition of Lates calcarifer (Latidae). Aeanthopagrus berda (Sparidae) and Lutjanus agentimaculatus (Lutjanidae) dominated total community biomass. During high-tide periods, intertidal forested areas were important habitats for juvenile and adult fish, with grand mean (+1 SE) density and biomass of 3.5_+2.4 fish m-3 and 10.9 _+ 4.5 g m-3, respectively. There was evidence of lower densities and less fish species using intertidal forests in the dry season (August, October), but high variances in catches masked any significant seasonality in mean fish biomass in this habitat. On ebb tides, most fish species (major families; Ambassidae, Leiognathidae, Atherinidae, Melanotaeniidae) moved to small shallow creeks, where mean (-+1 SE) low-tide density and biomass were 31.3_+12.4 fish m -2 and 29.0_+12.1 g m -z, respectively. Large variances in catch data masked any seasonality in densities and biomasses, but the mean number of species captured per netting in small creeks was lowest in the dry season (July, August). Species of Engraulidae and Clupeidae, which dominated high-tide catches in the forested areas during the wet season, appeared to move into the mainstream of the estuary on ebbing tides and were captured over accreting banks at low tide. Accreting banks supported a mean ( -+ 1 SE) density and biomass of 0.4 _+ 0.1 fish m- z and 1.7 + 0.3 g m- 2, respectively, at low tide. There were marked seasonal shifts in fish community composition in the estu

A Comparison of Fish Faunas Found in Pure Stands of Two Tropical Atlantic Seagrasses, Thalassia testudiunum and Syringodium filiforme

Quantitative samples of fish faunas found in pure stands of Thalassia testudlnum and Syringodium filiforme were taken using ®Pronoxfish. The fish faunas of the two habitats were compared for similarity of species, species diversity, and biomass to assess habitat equivalency of the two seagrass communities. Peter's (1971) method of analysing biogeographic data was used. The resulting cluster analysis using minimum distance showed all within habitat comparisons to cluster within a scalar distance of 99 while between habitat comparisons clustered at a scalar distance of 6.1 indicating that the associated faunas of the two seagrasses are highly dissimilar. Mean fish biomass of samples from Thalassia was 3.15 g/m2 while that of samples from Syringodium was 0.65 g/m2. These values were significantly different (df = 20, t = 5.33, p<.001). Mean diversity (H') of samples from Thalassia was 2.38 and that of samples from Syringodium was 2.11. These values are not significantly different (df = 20, t = 1.26, p>.05). Differences between sea grass fish faunas were obvious both at family and species levels. From these data it seems that the two seagrass types are not equivalent as fish habitats. The reasons for this lack of equivalency probably related to substrate, relatively higher patchiness in the Thalassia habitats, and environmental structure imposed by blade morphology.