Review of river fisheries valuation in West and Central Africa

This paper provides a review of the valuation of river fisheries in West and Central Africa. It is the general perception that, compared to the biological and ecological aspects of river fisheries, this particular subject area has received relatively little attention. Economic valuation is concerned with finding expression for what is important in life for human society. It should, therefore, be a central and integral part of government decision-making and policy. The review started with concepts and methods for valuation. Three main types of valuation techniques were identified: conventional economic valuations, economic impact assessments and socioeconomic investigations, and livelihood analysis. On the basis of a literature review, valuation information was then synthesized for the major regional river basins and large lakes, and also used to develop a series of national fisheries profiles. To supplement this broad perspective, a series of case studies are also presented, which focus in particular on the impact of changes in water management regime. Finally, the paper presents an assessment of the three main types of valuation methodology and a set of conclusions and recommendations for future valuation studies.

Age, size, and sexual maturity of channeled whelk (Busycotypus canaliculatus) in Buzzards Bay, Massachusetts

With the southern New England lobster fishery in distress, lobster fishermen have focused more effort toward harvesting channeled whelk (Busycotypus canaliculatus). However, minimal research has been conducted on the life history and growth rates of channeled whelk. Melongenid whelks generally grow slowly and mature late in life, a characteristic that can make them vulnerable to overfishing as fishing pressure increases. We sampled channeled whelk from Buzzards Bay, Massachusetts, in August 2010 and in July 2011, studied their gonad development by histology, and aged them by examining opercula. Males had a slower growth rate and a lower maximum size than females. Male whelk reached 50% maturity (SM50) at 115.5 mm shell length (SL) and at the age of 6.9 years. Female whelk reached SM50 at 155.3 mm SL and at the age of 8.6 years. With a minimum size limit of 69.9 mm (2.75 in) in shell width, males entered the fishery at 7.5 years, a few months after SM50, but females entered the fishery at 6.3 years, approximately 2 years before SM50. Increased fishing pressure combined with slow growth rates and the inability to reproduce before being harvested can easily constrain the long-term viability of the channeled whelk fishery in Massachusetts.

The biology, ecology and impact of the Nile perch, Lates niloticus in lakes Victoria, Kyoga and Nabugabo and the future of the fisheries

Nile perch (Mputa), Lates niloticus was introduced into Lakes Victoria and Kyoga from lake Albert to increase fish production of these lakes by feeding on and converting the small sized haplochromines (Nkejje) which were abundant in these lakes into a larger table fish. It was, however, feared that Nile perch would prey on and deplete stocks of the native fishes and affect fish species diversity. Nile perch became well established and is currently among the three most important commercial species. It is presently the most important export fish commodity from Uganda. Considerable changes have taken place in fishery yield, and in life history characteristics of the Nile perch itself since the predator got established in Lakes Victoria and Kyoga.

Physical modeling of processes of sediment transport in inlets

During the transformation of the low tide to the high tide, an exactly inverse phenomenon is occurred and the high tidal delta is formed at the mouth upstream. Increasing the tidal range does not affect the nature of this phenomenon and just change its intensity. In this situation, the inlet will be balance over time. A new relationship between equilibrium cross section and tidal prism for different tidal levels as well as sediment grading has been provided which its results are corresponded with results of numerical modeling. In the combination state, the wave height significantly affects the current and sedimentary pattern such that the wave height dimensionless index (Hw/Ht) determines the dominant parameter (the short period wave or tide) in the inlet. It is notable that in this state, the inlet will be balanced over the time. In order to calculate sedimentary phenomena, each of which are individually determined under solely wave and only tide conditions and then they are added. Estimated values are similar to numerical modeling results of the combination state considering nonlinear terms. Also, it is clear that the wave and tide performance is of meaning in the direct relationship with the water level. The water level change causes variations of the position of the breaking line and sedimentary active area. It changes the current and sedimentary pattern coastward while does not change anything seaward. Based on modeling results of sediment transport due to the wave, tide and their combination, it could be said that the erosion at the mouth due to the wave is less than that due to the wave and tide combination. In these situations, tide and wave-tide combination increase the low tidal and high tidal delta volume, respectively. Hence, tide plays an effective role in changing sedimentary phenomena at the channel and mouth downstream. Whereas, short period and combined waves have a crucial role in varying the morphology and sediment transport coast ward.

Teaching Change: Information Literacy Collaboration at Texas A&M University at Galveston

While college students use a wide array of technologies to access information, their skills at determining what is relevant, in a university setting and in life, are poor. Many of these skills have to be taught in college courses. Instruction must be performed by a collaborative team using technologies that effectively reach students. This team must be ready to go into the classroom when needed and be able to address the problem whenever the student needs assistance. The results will be better writing and better research skills that will not only benefit the faculty but will lead to lifelong learning.

Distribution, movements, and habitat use of small striped bass (Morone saxatilis) across multiple spatial scales

Distribution, movements, and habitat use of small (<46 cm, juveniles and individuals of unknown maturity) striped bass (Morone saxatilis) were investigated with multiple techniques and at multiple spatial scales (surveys and tag-recapture in the estuary and ocean, and telemetry in the estuary) over multiple years to determine the frequency and duration of use of non-natal estuaries. These unique comparisons suggest, at least in New Jersey, that smaller individuals (<20 cm) may disperse from natal estuaries and arrive in non-natal estuaries early in life and take up residence for several years. During this period of estuarine residence, individuals spend all seasons primarily in the low salinity portions of the estuary. At larger sizes, they then leave these non-natal estuaries to begin coastal migrations with those individuals from nurseries in natal estuaries. These composite observations of frequency and duration of habitat use indicate that non-natal estuaries may provide important habitat for a portion of the striped bass population.

Demographic characteristics of exploited tropical lutjanids: a comparative analysis

Demographic parameters from seven exploited coral reef lutjanid species were compared as a case study of the implications of intrafamily variation in life histories for multispecies harvest management. Modal lengths varied by 4 cm among four species (Lutjanus fulviflamma, L. vitta, L. carponotatus, L. adetii), which were at least 6 cm smaller than the modal lengths of the largest species (L. gibbus, Symphorus nematophorus, Aprion virescens). Modal ages, indicating ages of full selection to fishing gear, were 10 years or less for all species, but maximum ages ranged from 12 (L. gibbus) to 36 years (S. nematophorus). Each species had a unique growth pattern, with differences in length-at-age and mean asymptotic fork length (L∞), but smaller species generally grew fast during the first 1–2 years of life and larger species grew more slowly over a longer period. Total mortality rates varied among species; L. gibbus had the highest mortality and L. fulviflamma, the lowest mortality. The variability in life history strategies of these tropical lutjanids makes generalizations about lutjanid life histories difficult, but the fact that all seven had characteristics that would make them particularly vulnerable to fishing indicates that harvest of tropical lutjanids should be managed with caution.

The food habits of hatchery-produced pond-cultured shad (Alosa sapidissima) reared to a length of two inches

The present study was aimed at determining the food habits of hatchery-produced, pond-cultured shad (Alosa sapidissima) reared to a total length of approximately two inches. More specifically, the objectives were to determine: (1) That point in life at which young shad start to consume food; (2) What type or types of food the young shad consume at the onset of feeding; (3) Food changes, if any, which occur with age and growth in size up to the arbitrarily designated total length of two inches. The plan was that the shad larvae be introduced into an outdoor rearing pond previously fertilized, and that the larvae be dependent upon the plankton for food as they would be under natural conditions.

A remarkable new species of Psednos (Teleostei: Liparidae) from the western North Atlantic Ocean

Psednos rossi new species (Teleostei: Liparidae) is described from two specimens collected in the North Atlantic Ocean off Cape Hatteras, North Carolina, at depths of 500–674 m. Psednos rossi belongs to the P. christinae group, which includes six other species and is characterized by 46–47 vertebrae and the absence of a coronal pore. Psednos rossi differs from those six species by having characters unique within the genus: straight spine, body not humpbacked at the occiput, and a very large mouth with a vertical oral cleft. Other distinguishing characters include a notched pectoral fin with 15–16 rays, eye 17–19% SL, and color in life orange-rose. With P. rossi, the genus Psednos as currently known includes 26 described and five undescribed species of small meso- or bathypelagic liparids from the Atlantic, Pacific, and Indian Oceans.