Relationships between Larval and Juvenile Abundance of Winter-Spawned Fishes in North Carolina, USA

We analyzed the relationships between the larval and juvenile abundances of selected estuarine-dependent fishes that spawn during the winter in continental shelf waters of the U.S. Atlantic coast. Six species were included in the analysis based on their ecological and economic importance and relative abundance in available surveys: spot Leiostomus xanthurus, pinfish Lagodon rhomboides, southern flounder Paralichthys lethostigma, summer flounder Paralichthys dentatus, Atlantic croaker Micropogonias undulatus, and Atlantic menhaden Brevoortia tyrannus. Cross-correlation analysis was used to examine the relationships between the larval and juvenile abundances within species. Tests of synchrony across species were used to find similarities in recruitment dynamics for species with similar winter shelf-spawning life-history strategies. Positive correlations were found between the larval and juvenile abundances for three of the six selected species (spot, pinfish, and southern flounder). These three species have similar geographic ranges that primarily lie south of Cape Hatteras. There were no significant correlations between the larval and juvenile abundances for the other three species (summer flounder, Atlantic croaker, and Atlantic menhaden); we suggest several factors that could account for the lack of a relationship. Synchrony was found among the three southern species within both the larval and juvenile abundance time series. These results provide support for using larval ingress measures as indices of abundance for these and other species with similar geographic ranges and winter shelf-spawning life-history strategies.

Seasonal foods, gonadal maturation, and length-weight relationships for nine fishes commonly captured by shrimp trawl on the Northwest Gulf of Mexico Continental Shelf

Recent emphasis on ecosystem approaches to fisheries management renews interest in, and the need for, trophic information about fish communities. A program was started in 1980 at the National Marine Fisheries Service Galveston Laboratory to develop a trophic database for continental shelf fishes. Collections were made during 1982-1983 that were processed but never published, yet the data remain valid today for historical purposes and for delimiting food web components within ecosystem assessments. I examined spring, summer, and fall foods in offshore populations of nine common species of trawl-susceptible fishes, with particular reference to predation on commercial penaeid shrimps (Farfantepenaeus and Litopenaeus). Diets were evaluated with the Index of Relative Importance (IRI) which combines the occurrence, number, and weight of each food item. Bank sea bass (Centropristis ocyurus) and bighead searobin (Prionotus tribulus) primarily consumed crabs, more so by larger than smaller fish. Inshore lizardfish (Synodus foetens) was almost entirely piscivorous. Ocellated flounder (Ancylopsetta ommata) consumed fishes, crabs, and stomatopods. Dwarf sand perch (Diplectrum bivittatum), blackwing searobin (Prionotus rubio), rock sea bass (Centropristis philadelphica), southern kingfish (Menticirrhus americanus), and red snapper (Lutjanus campechanus) fed mainly on shrimps. Most fish diets varied with respect to size (age), time of day, area sampled, depth, or season. Rimapenaeus and Sicyonia were the most frequently identified shrimp genera - only five Farfantepenaeus and no Litopenaeus were identified in almost 4,300 fish stomachs. I also examined gonadal development and documented fish length-weight relationships. Ripe gonads were most frequently found during summer in dwarf sand perch, during fall in ocellated flounder and bighead searobin, and during spring for other species, except no ripe red snapper or bank sea bass were collected. Rock sea bass was found to be a protogynous hermaphrodite, while dwarf sand perch is a synchronous hermaphrodite. Only ocellated flounder and southern kingfish exhibited sex-related differences in length-weight relationships. (PDF contains 40 pages.)

Species and size relationships within schools of yellowfin and skipjack tuna as indicated by catches in the Eastern Tropical Pacific Ocean

ENGLISH: Yellowfin tuna, Neothunnus macropterus, and skipjack tuna, Katsuwonus pelamis, are fished intensively off the west coast of the Americas in an area from about the California-Mexico border in the north to the Peru-Chile border in the south. The historical development of this fishery, and its expansion by the long-range California fleets of bait and purse-seine vessels, are well documented by Godsil (1938), Scofield (1951) and Shimada and Sehaefer (1956). The quarterly distribution of the tuna catches within this area has been reported for some recent years by Alverson (1959). SPANISH: Los atunes aleta amarilla, Neothunnus macropterus, y barrilete, Katsuwonus pelamis, son pescados con intensidad frente a la costa occidental del continente americano, en un área comprendida más o menos entre la frontera California-México en el norte y el límite Perú-Chile en el sur. El desarrollo histórico de esta pesquería y la expansión que le han dado las flotas californianas de largo radio de acción, formadas por los barcos de carnada y rederos, están bien documentados por Godsil (1938), Scofield (1951) y Shimada y Schaefer (1956). La distribución trimestral de las pescas de atún dentro de esta área ha sido tratada por Alverson (1959) con referencia a años recientes.

The relationships between length and weight of yellowfin tuna (Neothunnus macropterus) and skipjack tuna (Katsuwonus pelamis) from the Eastern Tropical Pacific Ocean

ENGLISH: The purposes of the Convention which established the Inter-American Tropical Tuna Commission have been discussed in the Commission's Annual Report for 1950-51 (Schaefer, 1952) and in subsequent Annual Reports. One of its functions is to gather and report on biological information for the tunas of the Eastern Tropical Pacific, the yellowfin tuna (Neothunnus macropterus) and skipjack tuna (Katsuwonus pelamis). This report gives the results of a study of the relationships between the length and the weight of individuals of each of these species, derived from samples of fish of commercial sizes captured during the course of regular fishing operations in several areas of the Eastern Tropical Pacific Ocean SPANISH: Los propósitos de la Convención que estableció la Comisión Interamericana del Atún Tropical han sido expuestos en el Informe Anual de dicho organismo correspondiente a 1950-51 (Schaefer, 1952), y en los siguientes informes anuales. Una de sus funciones es la de recoger información biológica sobre los atunes del Pacífico Oriental Tropical, es decir, el aleta amarilla (Neothunnus macropterus) y el barrilete (Katsuwonus pelamis) y darla a conocer a las partes interesadas. El presente trabajo informativo proporciona los resultados de un estudio de las relaciones entre la longitud y el peso tomados en individuos de cada una de estas especies, mediante muestreo en pescados de tamaños comerciales capturados en el curso de operaciones regulares de pesca, en diversas área del Océano Pacífico Oriental Tropical.

Some relationships of meteorological, hydrographic, and biological variables in the Gulf of Panama

ENGLISH: An average of 78 m. of water was vertically displaced by wind-driven upwelling during the dry season (January-April) in Panama Bay at the head of the Gulf of Panama. The standing crop of phytoplankton and its productivity were significantly greater during the months of upwelling than during the rainy season. Equivalent results were found by three different methods used to calculate photosynthesis: direct measurement with radiocarbon; increase of dissolved oxygen in the water column; and decrease of phosphate-phosphorus in the water column. About 90 g. of carbon per square meter of sea surface were fixed by the phytoplankton during each upwelling season (January-April) and about 90 g. of carbon were fixed during each rainy season (May-December) resulting in an annual production of about 180 g. of carbon per square meter of sea surface SPANISH: Un promedio de 78 m. de agua fué desplazado verticalmente por la fuerza de los vientos que ocasionan el fenómeno conocido por afloramiento durante la estación seca (enero a abril) en la Bahía de Panamá, a la cabeza del Golfo de Panamá. La cosecha estable de fitoplancton y su productividad fueron significativamente mayores durante los meses de afloramiento, que durante la estación lluviosa. Se obtuvieron resultados equivalentes por medio de tres diferentes métodos usados para calcular la fotosíntesis: medición directa con radiocarbono, aumento del oxígeno disuelto en la columna de agua, y disminución del fosfato-fósforo en la columna de agua. Por medio del fitoplancton durante cada estación de afloramiento (enero-abril), se fijaron alrededor de 90 g. de carbono por metro cuadrado de la superficie del mar, y durante cada estación lluviosa (mayo-diciembre) se fijaron 90 g. de carbono lo que resulta en una producción anual de aproximadamente 180 g. de carbono por metro cuadrado de la superficie del mar.

Length-weight relationships of the anchoveta, Cetengraulis mysticetus, in the Gulf of Panama

ENGLISH: Knowledge of the length-frequency distribution and the length-weight relationships of the anchoveta is essential for converting the catch statistics of that species from pounds to numbers of fish. Such conversions are necessary for various types of investigations, especially those involving estimation of the population size and mortality rates. The analysis of the results of a recent tagging program conducted with anchovetas in the Gulf of Panama (Bayliff, 1965) requires that such conversions be made. Length-frequency data for the anchoveta have already been collected and published (Howard and Landa, 1958; Bayliff, 1964). The present report deals with length-weight data from fish collected in various .areas of the Gulf of Panama in all months of the year and in several different years. Opportunity is thus afforded to compare the length-weight relationships of fish of different year classes in different areas, months, and years. SPANISH: El conocimiento de la distribución de la frecuencia de longitud y de las relaciones entre la longitud y el peso de la anchoveta es esencial en las estadísticas de captura de esta especie para la conversión de peso en libras a número de peces. Estas conversiones son necesarias para varios tipos de investigación, especialmente las que se refieren a la estimación del tamaño de la población y de las tasas de mortalidad. Estas conversiones se requieren para analizar los resultados de un programa reciente de marcación de anchovetas en el Golfo de Panamá (Bayliff, 1965). Los datos de la frecuencia de longitud de la anchoveta ya han sido recolectados y publicados (Howard y Landa, 1958; Bayliff, 1964). El presente informe trata de los datos de longitud y peso de los peces recolectados en varias áreas del Golfo de Panamá durante todos los meses del año y durante varios años. Esto ofrece la oportunidad de comparar las relaciones entre la longitud y el peso de peces pertenecientes a varias clases anuales en áreas, meses y años diferentes.

Eliciting and using stakeholder input to guide Puget Sound nearshore restoration decisionmaking

The goal of the Puget Sound Nearshore Ecosystem Restoration Project (PSNERP) is to improve system-wide functionality of nearshorei ecosystem processes. To achieve that goal, PSNERP plans to strategically restore nearshore sites throughout Puget Sound. PSNERP scientists are assessing changes to the nearshore, and will recommend an environmentally strategic restoration portfolio. Yet, PSNERP also needs stakeholder input to design a socially strategic portfolio. This research investigates the values and preferences of stakeholders in the Whidbey Sub-Basin of Puget Sound to help PSNERP be both socially and environmentally strategic. This investigation may be repeated in the six other Puget Sound Sub-Basins. The results will guide restoration portfolio design and future stakeholder involvement activities. This study examines four areas of stakeholder values and preferences: 1) beliefs about the causes, solutions, and severity of nearshore problems; 2) priorities for nearshore features, shoreforms, developments, and restoration objectives; 3) thoughts about ecosystem servicesiii and trade-offs among them; and 4) visions of a future, restored Puget Sound nearshore and the role of science in attaining this vision. The study is framed by two hypotheses from the Advocacy Coalition Framework (ACF), which suggests that groups of policy advocates form around shared “policy core beliefs” which can transcend traditional categories of stakeholders.(PDF contains 3 pages)

The politics of participation: Evaluating stakeholder equity in co-management regimes

Within natural resource management, there is increasing criticism of the traditional model of top-down management as a method of governance, as researchers and managers alike have recognized that resources can frequently be better managed when stakeholders are directly involved in management. As a result, in recent years the concept of co-management of natural resources, in which management responsibilities are shared between the government and stakeholders, has become increasingly popular, both in the academic literature and in practice. However, while co-management has significant potential as a successful management tool, the issue of equity in co-management has rarely been addressed. It is necessary to understand the differential impacts on stakeholders of co-management processes and the degree to which diverse stakeholders are represented within co-management. Understanding the interests of various stakeholders can be a way to more effectively address the distributional and social impacts of coastal policies, which can in turn increase compliance with management measures and lead to more sustainable resource management regimes. This research seeks to take a closer look at the concepts of co-management and participation through a number of case studies of marine protected areas (MPAs) in the Caribbean. (PDF contains 4 pages)

Investigations of certain eco-physiological characteristics of the broad and long-pincered crayfish in connection with their interspecific relationships. [Translation from: Lietuvas TSR Mokslu Akademijos Darbai, C Serija 2(40), 279-286, 1966.]

The results are described of eco-physiological investigations of the broad-pincered (Astacus astacus L.J.) crayfish and the long-pincered (Astacus astacus Esch.) crayfish, conducted in 1963—64 in the Institute of Zoology and Parasitology of the Academy of Science of the Lithuanian SSR, for the purpose of studying the interspecific relationship of these two species. In the course of the investigation were determined: the influence of the temperature of the environment on the consumption of oxygen by full grown individuals of both species and on the respiratory movements of the scaphognathites, the threshold temperatures and the saturation of the water by oxygen, the diel activity in the winter period.

An introduction to the 4-beaches survey and the Stakeholder Workshops

1) The 4-beaches survey was the first of its kind on Lake Victoria. Drawing on Participatory Rural Appraisal (PRA) techniques, four landing sites around the lake were selected for long-term monitoring from March 2000 through to October 2001. 2)Held in all the 3 riparian countries of Lake Victoria the stakeholders' workshops aimed to assess the necessity of fisheries management for Lake Victoria and to identify who the stakeholders in fisheries management would be.

Methodologies of the 4-beaches Survey and Stakeholder Workshops

As it is clearly indicated in the title of this book section, it overviews the methodologies used in the 4-beaches Survey and in the various Stakeholders' Workshops held in all the three riparian countries of the Lake Victoria.

Spatial and seasonal relationships between Pacific harbor seals (Phoca vitulina richardii) and their prey, at multiple scales

Knowing where pinnipeds forage is vital to managing and protecting their populations, and for assessing potential interactions with fisheries. We assessed the spatial relationship between the seasonal distribution of Pacific harbor seals (Phoca vitulina richardii) outfitted with satellite transmitters and the seasonal distributions of potential harbor seal prey species in San Francisco Bay, California. Pearson’s correlation coefficients were calculated between the number of harbor seal locations in an area of the San Francisco Bay and the abundance of specific prey species in the same area. The influence of scale on the analyses was assessed by varying the scale of analysis from 1 to 10 km. There was consistency in the prey species targeted by harbor seals year-round, although there were seasonal differences between the most important prey species. The highest correlations between harbor seals and their prey were found for seasonally abundant benthic species, located within about 10 km of the primary haul-out site. Probable foraging habitat for harbor seals was identified, based on areas with high abundances of prey species that were strongly correlated with harbor seal distribution. With comparable local data inputs, this approach has potential application to pinniped management in other areas, and to decisions about the location of marine reserves designed to protect these species.

Multiple stable reference points in oyster populations: biological relationships for the eastern oyster (Crassostrea virginica) in Delaware Bay

Abstract—In the first of two companion papers, a 54-yr time series for the oyster population in the New Jersey waters of Delaware Bay was analyzed to develop biological relationships necessary to evaluate maximum sustainable yield (MSY) reference points and to consider how multiple stable points affect reference point-based management. The time series encompassed two regime shifts, one circa 1970 that ushered in a 15-yr period of high abundance, and a second in 1985 that ushered in a 20-yr period of low abundance. The intervening and succeeding periods have the attributes of alternate stable states. The biological relationships between abundance, recruitment, and mortality were unusual in four ways. First, the broodstock–recruitment relationship at low abundance may have been driven more by the provision of settlement sites for larvae by the adults than by fecundity. Second, the natural mortality rate was temporally unstable and bore a nonlinear relationship to abundance. Third, combined high abundance and low mortality, though likely requiring favorable environmental conditions, seemed also to be a self-reinforcing phenomenon. As a consequence, the abundance –mortality relationship exhibited both compensatory and depensatory components. Fourth, the geographic distribution of the stock was intertwined with abundance and mortality, such that interrelationships were functions both of spatial organization and inherent populatio

Prosomal-width-to-weight relationships in American horseshoe crabs (Limulus polyphemus): examining conversion factors used to estimate landings

Horseshoe crabs (Limulus polyphemus) are valued by many stakeholders, including the commercial fishing industry, biomedical companies, and environmental interest groups. We designed a study to test the accuracy of the conversion factors that were used by NOAA Fisheries and state agencies to estimate horseshoe crab landings before mandatory reporting that began in 1998. Our results indicate that the NOAA Fisheries conversion factor consistently overestimates the weight of male horseshoe crabs, particularly those from New England populations. Because of the inaccuracy of this and other conversion factors, states are now mandated to report the number (not biomass) and sex of landed horseshoe crabs. However, accurate estimates of biomass are still necessary for use in prediction models that are being developed to better manage the horseshoe crab fishery. We recommend that managers use the conversion factors presented in this study to convert current landing data from numbers to biomass of harvested horseshoe crabs for future assessments.

Reconstruction of original body size and estimation of allometric relationships for the longfin inshore squid (Loligo pealeii) and northern shortfin squid (Illex illecebrosus)

Quantification of predator-prey body size relationships is essential to understanding trophic dynamics in marine ecosystems. Prey lengths recovered from predator stomachs help determine the sizes of prey most influential in supporting predator growth and to ascertain size-specific effects of natural mortality on prey populations (Bax, 1998; Claessen et al., 2002). Estimating prey size from stomach content analyses is often hindered because of the degradation of tissue and bone by digestion. Furthermore, reconstruction of original prey size from digested remains requires species-specific reference materials and techniques. A number of diagnostic guides for freshwater (Hansel et al., 1988) and marine (Watt et al., 1997; Granadeiro and Silva, 2000) prey species exist; however they are limited to specific geographic regions (Smale et al., 1995; Gosztonyi et al., 2007). Predictive equations for reconstructing original prey size from diagnostic bones in marine fishes have been developed in several studies of piscivorous fishes of the Northwest Atlantic Ocean (Scharf et al., 1998; Wood, 2005). Conversely, morphometric relationships for cephalopods in this region are scarce despite their importance to a wide range of predators, such as finfish (Bowman et al., 2000 ; Staudinger, 2006), elasmobranchs (Kohler, 1987), and marine mammals (Gannon et al., 1997; Williams, 1999).