The influence of disparate levels of submersed aquatic vegetation on largemouth bass population characteristics in a Georgia reservoir

Population characteristics of largemouth bass (Micropterous salmoides L.) including growth, body condition (relative weight), size structure, survival, and fecundity were examined in relation to abundance of submersed aquatic vegetation (SAV) coverage (primarily hydrilla Hydrilla verticillata L.f. Royle) in three major embayments of Lake Seminole, Georgia. Relative weight, fecundity, and growth of large-mouth bass in the Spring Creek embayment (76% areal SAV coverage) was considerably less than measured in the Chattahoochee and Flint river arms that contained lower SAV coverages (26% and 32%). It took fish 1.8 years longer to reach 406 mm in Spring Creek compared to the Chattahoochee-Flint arms. Consequently, fish were smaller in Spring Creek than in the Chattahoochee-Flint arms. In addition, due to slower growth rates and lower fecundity-to-body weight relation, we predicted a 47% reduction in total potential ova production in Spring Creek compared to the other two reservoir embayments. The annual survival rate of 3 to 10 year old largemouth bass was higher in Spring Creek (84%) than in the Chattahoochee-Flint arms (72%) and suggested either lower harvest and/or lower accessibility of particularly larger fish to angling in dense vegetation. Contrary to our expectaions, the fit between number-at-age and age in a catch-curve regression was weaker for fish collected in Spring Creek and suggested greater recruitment variability has occurred over time in this highly vegetated embayment. In Lake Seminole, spatial differences in largemouth bass population characterstics were associated with disparate levels of SAV. Our data suggest that a reduction in hydrilla, but maintenance of an intermediate level of SAV in Spring Creek, should improve largermouth bass population in this arm of the reservoir.

Fish assemblages and benthic habitats of Buck Island Reef National Monument (St. Croix, U.S. Virgin Islands) and the surrounding seascape: A characterization of spatial and temporal patterns

Since 1999, NOAA’s Biogeography Branch of the Center for Coastal Monitoring and Assessment (CCMA-BB) has been working with federal and territorial partners to characterize, monitor, and assess the status of the marine environment around northeastern St. Croix, U.S. Virgin Islands. This effort is part of the broader NOAA Coral Reef Conservation Program’s (CRCP) National Coral Reef Ecosystem Monitoring Program (NCREMP). With support from CRCP’s NCREMP, CCMA conducts the “Caribbean Coral Reef Ecosystem Monitoring project” (CREM) with goals to: (1) spatially characterize and monitor the distribution, abundance, and size of marine fauna associated with shallow water coral reef seascapes (mosaics of coral reefs, seagrasses, sand and mangroves); (2) relate this information to in situ fine-scale habitat data and the spatial distribution and diversity of habitat types using benthic habitat maps; (3) use this information to establish the knowledge base necessary for enacting management decisions in a spatial setting; (4) establish the efficacy of those management decisions; and (5) develop data collection and data management protocols. The monitoring effort in northeastern St. Croix was conducted through partnerships with the National Park Service (NPS) and the Virgin Islands Department of Planning and Natural Resources (VI-DPNR). The geographical focal point of the research is Buck Island Reef National Monument (BIRNM), a protected area originally established in 1961 and greatly expanded in 2001; however, the work also encompassed a large portion of the recently created St. Croix East End Marine Park (EEMP). Project funding is primarily provided by NOAA CRCP, CCMA and NPS. In recent decades, scientific and non-scientific observations have indicated that the structure and function of the coral reef ecosystem around northeastern St. Croix have been adversely impacted by a wide range of environmental stressors. The major stressors have included the mass Diadema die off in the early 1980s, a series of hurricanes beginning with Hurricane Hugo in 1989, overfishing, mass mortality of Acropora corals due to disease and several coral bleaching events, with the most severe mass bleaching episode in 2005. The area is also an important recreational resource supporting boating, snorkeling, diving and other water based activities. With so many potential threats to the marine ecosystem and a dramatic change in management strategy in 2003 when the park’s Interim Regulations (Presidential Proclamation No. 7392) established BIRNM as one of the first fully protected marine areas in NPS system, it became critical to identify existing marine fauna and their spatial distributions and temporal dynamics. This provides ecologically meaningful data to assess ecosystem condition, support decision making in spatial planning (including the evaluation of efficacy of current management strategies) and determine future information needs. The ultimate goal of the work is to better understand the coral reef ecosystems and to provide information toward protecting and enhancing coral reef ecosystems for the benefit of the system itself and to sustain the many goods and services that it offers society. This Technical Memorandum contains analysis of the first six years of fish survey data (2001-2006) and associated characterization of the benthos (1999-2006). The primary objectives were to quantify changes in fish species and assemblage diversity, abundance, biomass and size structure and to provide spatially explicit information on the distribution of key species or groups of species and to compare community structure inside (protected) versus outside (fished) areas of BIRNM. (PDF contains 100 pages).

Die Bedeutung biologischer Daten aus der deutschen Seelachsfischerei für Bestandsabschätzung und Management

Since 1999, the ICES Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak assesses the saithe stock in the North Sea, Skagerrak and west of Scotland as a single stock unit. The sampling, evaluation and role of biological data from the German saithe fishery in the assessment are described. The German data showed similar trends as observed in French and Norwegian series. Based on these estimates, the spawning stock recovered to more than 200 000 t due to reductions in quotas and exploitation rates. Thus, the production of the stock increased also in combination with good recruitment and positive trends in spawning stock size and landings were projected for 2002. The biological data derived from the German saithe fishery dominated the assessment of stock size, structure and exploitation. This fact encourages a continuation of the described analyses based on sampling onboard fishing vessels and fish markets by the Institute for Sea Fisheries. The successful collaboration with the saithe fishing industry is judged as an important contribution to the sustainable management of fish stocks.

Distribution of Oreochromis niloticus (L.) in the Ugandan waters of Lake Victoria

The Lake Victoria fish fauna was dominated by cichlids before the establishment of the exotic species Oreochromis niloticus (L.) and Latus niloticus (L.). With the alterations in the ecology of Lake Victoria, changes may be expected to occur in the population dynamics of the fish species. In two zones of Lake Victoria, the size structure, distribution and abundance, condition factors, length-weight relationship and sex ratios of O. niloticus were determined. Larger fish were found in zone II than in zone III, where very few larger fish were recorded. More O. niloticus were caught in zone III, especially in Itome Bay, than in zone II but catch by weight was greater in zone II. More males than females were encountered in both zones. Oreochromis niloticus had similar condition factors in both zones.

Reprodução de peixes de riachos: uma abordagem comparativa entre as estratégias r e K

No presente trabalho, objetivou-se caracterizar a estratégia reprodutiva, enfatizando o investimento energético, de duas espécies de peixe do rio Ubatiba, Maricá, Rio de Janeiro: Parotocinclus maculicauda (K-estrategista) e Astyanax hastatus (r-estrategista). Foram realizadas coletas bimestrais de Junho de 2010 a Abril de 2011 totalizando 236 exemplares amostrados de A. hastatus e 234 de P. maculicauda. Para cada exemplar foram registrados os dados de comprimento padrão (Cp, cm), peso total (Pt, g), peso gonadal (Pg, g), sexo e estádio de maturação. Através da estrutura de tamanho, observamos que as fêmeas atingem maior comprimento, em relação aos machos, para as duas espécies. A relação peso/ comprimento evidenciou para ambas as espécies, crescimento alométrico negativo (inferior a 3), demonstrando crescimento mais longelíneo. Para a proporção sexual, o teste χ2 foi aplicado e indicou que, para as duas espécies, há significativamente mais fêmeas. A distribuição sexual no ano mostrou que as fêmeas se mantêm em maioria durante todo o ano para P. maculicauda. Para A. hastatus este padrão também se mantém, porém com exceção do bimestre Novembro/Dezembro, quando o número de machos torna-se um pouco maior. O tamanho de primeira maturação mostrou-se o mesmo para ambas as espécies (2,5 a 3,0 cm). A variação temporal da freqüência de indivíduos reprodutivos e não reprodutivos juntamente com a distribuição temporal dos valores individuais de IGS mostrou que P. maculicauda se reproduz com maior intensidade nas estações chuvosas (Setembro a Abril), reduzindo sua atividade reprodutiva de maneira significativa nas estações secas (Maio a Agosto). Já A. hastatus demonstrou regular atividade reprodutiva durante todo o ano com pequeno pico no bimestre Novembro/ Dezembro. Desova do tipo total foi registrada para Astyanax, enquanto que para Parotocinclus registrou-se desova parcelada em três lotes. Em ambas as espécies foi observada relação inversa entre volume e a quantidade de ovócitos produzidos, com A. hastatus produzindo muitos ovócitos (fecundidade: 463 + 213 ovócitos/grama de peixe) de reduzido volume (diâmetro = 800 μm e volume = 0,26 mm3) e P. maculicauda produzindo número bem inferior (fecundidade: 47 + 13 ovócitos/grama de peixe), porém com volume superior (diâmetro = 1.600 μm e volume = 2,14 mm3). Com isso o valor energético relativo também se mostrou superior, com A. hastaus produzindo ovócitos vitelogênicos com 0,4+ 0,08 cal/unidade e P. maculicauda produzindo os mesmos ovócitos com 1,8+ 1,1 cal/unidade. Para a produção energética total investida na produção de gametas, foi considerado o tipo de desova de cada espécie, com Astyanax investindo 50,5 + 24 calorias/grama/grama de peixe e Parotocinclus investindo 88,4 + 72,46 cal/grama/grama de peixe, porém sem diferenças significativas (Mann-Whitney; U =235,0, p=0,08), indicando, portanto que independente da estratégia adotada (r ou K), o gasto energético na produção de ovócitos é a mesma.

Stimulating investment in pearl farming in Solomon Islands: Final report

The overall objective of the project is the reduction of poverty in rural areas of Solomon Islands through creation of livelihoods based on sustainable aquaculture. This fits within the over-arching goals of the WorldFish Center in the Pacific to reduce poverty and hunger in rural communities, and with the Ministry of Fisheries and Marine Resources (MFMR) to stimulate rural development and to develop aquaculture. It has been recognised that the nature of the pearl farming industry means that a high chance of success requires a long term investment from an established pearl farming organisation. This project has been specifically designed to compile the elements of a pre-feasibility study to provide offshore pearl companies with sufficient information to investigate the potential for long-term investment in pearl farming in Solomon Islands. This report also includes the following 6 appendices: Appendix I) Past research and development on black-lip pearl oysters in Solomon Islands; Appendix II) Suitability of habitats in the Solomon Islands and other regions of the Pacific for growth of black-lip and silver-lip pearl oysters; Appendix III) Water temperature and cyclone frequency in the Solomon Islands and other key regions of the Pacific: implications for pearl farming; Appendix IV) Abundance, size structure and quality of silver-lip pearl oysters in Solomon Islands; Appendix V) Solomon Islands: the investment climate for pearl farming; Appendix VI) Pearl farming policy and management guidelines.

Observations on Fisheries Activities at Navassa Island

Unmanaged and unquantified artisanal fishing is ongoing at Navassa Island, a small oceanic island about 70 km west of Haiti that is part of the U.S. Caribbean Islands National Wildlife Refuge. Concern has been expressed regarding the possible impact of these fishing activities on reef resources, and no quantitative catch or effort data are available. However, informal qualitative observations made during a cruise in November 2002 suggest that escalation in fishing activity (and impact) has occurred since previous observations made in April 2000. Namely, size structure of fish was markedly reduced and the adoption of net fishing has allowed the exploitation of queen conch, Strombas gigas, and hawksbill turtles, Eretmochelys imbricata.

A Positive trajectory for corals at Little Cayman Island

Coral reefs are damaged by natural disturbances and local and global anthropogenic stresses. As stresses intensify, so do debates about whether reefs will recover after significant damage. True headway in this debate requires documented temporal trajectories for coral assemblages subjected to various combinations of stresses; therefore, we report relevant changes in coral assemblages at Little Cayman Island. Between 1999 and 2012, spatiotemporal patterns in cover, densities of juveniles and size structure of assemblages were documented inside and outside marine protected areas using transects, quadrats and measurements of maximum diameters. Over five years, bleaching and disease caused live cover to decrease from 26% to 14%, with full recovery seven years later. Juvenile densities varied, reaching a maximum in 2010. Both patterns were consistent within and outside protected areas. In addition, dominant coral species persisted within and outside protected areas although their size frequency distributions varied temporally and spatially. The health of the coral assemblage and the similarity of responses across levels of protection suggested that negligible anthropogenic disturbance at the local scale was a key factor underlying the observed resilience.

Coral reef ecosystems of St. John, U.S. Virgin Islands: spatial and temporal patterns in fish and benthic communities (2001-2009)

Scientific and anecdotal observations during recent decades have suggested that the structure and function of the coral reef ecosystems around St. John, U.S. Virgin Islands have been impacted adversely by a wide range of environmental stressors. Major stressors included the mass die-off of the long-spined sea urchin (Diadema antillarum) in the early 1980s, a series of hurricanes (David and Frederick in 1979, and Hugo in 1989), overfishing, mass mortality of Acropora species and other reef-building corals due to disease and several coral bleaching events. In response to these adverse impacts, the National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment, Biogeography Branch (CCMA-BB) collaborated with federal and territorial partners to characterize, monitor, and assess the status of the marine environment around the island from 2001 to 2012. This 13-year monitoring effort, known as the Caribbean Coral Reef Ecosystem Monitoring Project (CREM), was supported by the NOAA Coral Reef Conservation Program as part of their National Coral Reef Ecosystem Monitoring Program. This technical memorandum contains analysis of nine years of data (2001-2009) from in situ fish belt transect and benthic habitat quadrat surveys conducted in and around the Virgin Islands National Park (VIIS) and the Virgin Islands Coral Reef National Monument (VICR). The purpose of this document is to: 1) Quantify spatial patterns and temporal trends in (i) benthic habitat composition and (ii) fish species abundance, size structure, biomass, and diversity; 2) Provide maps showing the locations of biological surveys and broad-scale distributions of key fish and benthic species and assemblages; and 3) Compare benthic habitat composition and reef fish assemblages in areas under NPS jurisdiction with those in similar areas not managed by NPS (i.e., outside of the VIIS and VICR boundaries). This report provides key information to help the St. John management community and others understand the impacts of natural and man-made perturbations on coral reef and near-shore ecosystems. It also supports ecosystem-based management efforts to conserve the region’s coral reef and related fauna while maintaining the many goods and ecological services that they offer to society.

Coral reef ecosystems of Reserva Natural de La Parguera (Puerto Rico): spatial and temporal patterns in fish and benthic communities (2001-2007)

Since 1999, NOAA’s Center for Coastal Monitoring and Assessment, Biogeography Branch (CCMA-BB) has been working with federal and territorial partners to characterize monitor and assess the status of the marine environment in southwestern Puerto Rico. This effort is part of the broader NOAA Coral Reef Conservation Program’s (CRCP) National Coral Reef Ecosystem Monitoring Program (NCREMP). With support from CRCP’s NCREMP, CCMA conducts the “Caribbean Coral Reef Ecosystem Monitoring project” (CREM) with goals to: (1) spatially characterize and monitor the distribution, abundance and size of marine fauna associated with shallow water coral reef seascapes (mosaics of coral reefs, seagrasses, sand and mangroves); (2) relate this information to in situ fine-scale habitat data and the spatial distribution and diversity of habitat types using benthic habitat maps; (3) use this information to establish the knowledge base necessary for enacting management decisions in a spatial setting; (4) establish the efficacy of those management decisions; and (5) develop data collection and data management protocols. The monitoring effort of the La Parguera region in southwestern Puerto Rico was conducted through partnerships with the University of Puerto Rico (UPR) and the Puerto Rico Department of Natural and Environmental Resources (DNER). Project funding was primarily provided by NOAA CRCP and CCMA. In recent decades, scientific and non-scientific observations have indicated that the structure and function of the coral reef ecosystem in the La Parguera region have been adversely impacted by a wide range of environmental stressors. The major stressors have included the mass Diadema die off in the early 1980s, a suite of hurricanes, overfishing, mass mortality of Acropora corals due to disease and several coral bleaching events, with the most severe mass bleaching episode in 2005. The area is also an important recreational resource supporting boating, snorkeling, diving and other water based activities. With so many potential threats to the marine ecosystem several activities are underway or have been implemented to manage the marine resources. These efforts have been supported by the CREM project by identifying marine fauna and their spatial distributions and temporal dynamics. This provides ecologically meaningful data to assess ecosystem condition, support decision making in spatial planning (including the evaluation of efficacy of current management strategies) and determine future information needs. The ultimate goal of the work is to better understand the coral reef ecosystems and to provide information toward protecting and enhancing coral reef ecosystems for the benefit of the system itself and to sustain the many goods and services that it offers society. This Technical Memorandum contains analysis of the first seven years of fish survey data (2001-2007) and associated characterization of the benthos. The primary objectives were to quantify changes in fish species and assemblage diversity, abundance, biomass and size structure and to provide spatially explicit information on the distribution of key species or groups of species and to compare community structure across the seascape including fringing mangroves, inner, middle, and outer reef areas, and open ocean shelf bank areas.

Status of coral reef ecosystems in a marine managed area in St. Croix, USVI [poster]

This poster presents information on the status and trends of coral reef ecosystems in St. Croix, US Virgin Islands (USVI). Data were collected by NOAA’s Center for Coastal Monitoring and Assessment Biogeography Branch (CCMA-BB) from 2001-2006 at 1,275 random locations in and around Buck Island Reef National Monument (BIRNM). The main objective was to quantify changes in fish species and assemblage diversity, abundance, biomass and size structure; to provide spatially explicit information on the distribution of key species or groups of species; and to compare community structure inside versus outside of BIRNM.

A preliminary study on Dodecaceria pacifica (Fewkes)

In various areas along the coast in the vicinity of Monterey there are many colonies of the Polychaete worm Dodecaceria pacifica. An attempt has been made to find out something of the distribution, size, structure and the flora and fauna associated with these colonies.

Fishery of mud crab, Scylla serrata (Forskal) from Karwar waters

Catch data of Scylla serrata obtained in different gears from Karwar region during December 1983 — November 1984 indicated a sum of 9608 kg of landings of crabs. Majority of the crabs (89.57%) was found to be caught in backwaters by line fishing and cast nets. A considerable (10.43%) quantity of catch was also contributed by gill nets and shore-seines from inshore waters. A maximum of 1207 kg of crabs were landed in December, 1983. The size structure and sex-ratio of S. serrata varied with gear type and period.

Temperature-Dependent Growth and Life Cycle of Nemoura sichuanensis (Plecoptera: Nemouridae) in a Chinese Mountain Stream

Plecoptera constitute a numerically and ecologically significant component in mountain streams all over the world, but little is known of their life cycles in Asia. The life cycle of Nemoura sichuanensis and its relationship to water temperature was investigated during a 4-year study in a headwater stream (known as the Jiuchong torrent) of the Xiangxi River in Central China. Size structure histograms suggest that the life cycle was univoltine, and the relationships between the growth of Nemoura sichuanensis, physiological time, and effective accumulated water temperature were described using logistic regressions. The growth pattern was generally similar within year classes but growth rates did vary between year-classes. Our field data suggest a critical thermal threshold for emergence in Nemoura sichuanensis, that was close to 9 degrees C. The total number of physiological days required for completing larval development was 250 days. The effective accumulated water temperature was 2500 degree-days in the field. Development during the life cycle increased somewhat linearly with the physiological time and the effective accumulated water temperature, but some non-linear relationships were best developed by logistic equations.

黄土丘陵区油松天然次生林林窗特征与更新动态

研究了黄土丘陵区油松天然次生林林窗的形状、大小结构、分布、形成木特征及其更新状况.结果表明:在油松天然次生林中,林冠林窗(CG)和扩展林窗(EG)面积均呈以小林窗为主的偏态分布.CG平均面积为31.15 m2,以20~40 m2林窗的数量比和面积比最大,分别为38.24%和30.50%;EG平均面积为58.04 m2,以30~60 m2的数量比和面积比最大,分别为36.77%和27.79%,且CG的平均面积占EG平均面积的53.67%;林窗形状多呈椭圆形,高度多在14~16 m;林窗形成年龄以10~20年为主,占33.82%.林窗中基折和枯立木分别占形成木总数的47.66%和23.44%.林窗形成的主要因素是人为间伐或盗伐,树木衰老等引起的抗性下降、干旱、病虫害等也是导致树木死亡的原因之一;每个林窗中平均有1.89个形成木,其中以2株形成木的林窗最多.林窗形成木主要是油松,其次为山杨、白桦和辽东栎等.形成木的径级呈明显的偏态分布,以10~20 cm和21~30 cm径级最为普遍,分别占总数的25.0%和45.31%,与林窗面积偏态分布吻合;林窗内林木的更新状况好于林下,且油松幼苗不存在断层,而油松林下幼苗在年...