Reproductive characteristics of the Albemarle/Roanoke Striped Bass Stock

The principal striped bass population in North Carolina, the Albemarle/Roanoke (A/R) stock needs an up-to-date maturation and fecundity schedule for stock assessment models. The last study of this nature was conducted for the Albemarle Striped Bass Management Board in 1989-1990 by Olsen and Rulifson (1992) after the stock had crashed, and just before stock rebuilding took place. The same techniques as Olsen and Rulifson (1992) were used, with the addition of otolith microchemistry to determine spawning frequency. Striped bass were sampled by a fishery independent gillnet survey (North Carolina Division of Marine Fisheries) in the Albemarle Sound during the pre-spawn, spawning, and post-spawning periods. Additional sampling on and near the spawning grounds in the Roanoke River was conducted by an electroshocking survey (North Carolina Wildlife Resources Commission).  Fish were measured (FL and TL, mm) and weighed (g). Scales and otoliths were removed for ageing and otolith chemistry. Sex was determined, and gonads removed and weighed to determine the GSI and stage of reproduction. Ovaries were preserved for 24-48 hrs in a cold 10% buffered formalin solution, rinsed with distilled water, and then placed in a 70% ethyl alcohol solution for histological examination. Livers were weighed to determine the LSI and the K factors. The right sagittae otolith was sectioned and aged.  The left sagittae otolith was examined by LA-ICPMS to determine changes in concentrations of the elements Sr, Ba, Mg, and Mn over the life of the fish that reflect high salinity or freshwater environments. These changes will be compared to ages to determine the spawning history of the individual fish (i.e., whether spawning occurred each year or by skipping years known as “skipped spawning”). In addition, we should be able to tell what proportion of the spawning population are “residents” (living in Albemarle Sound), and anadromous (coming in from ocean overwintering habitats). The study will help the management of striped bass in North Carolina.  North Carolina’s marine resources are an integral part of the state, and provide economical and environmental benefits to all of North Carolina’s citizens.  By effectively managing the A/R striped bass stock, it will help restore, develop, and enhance North Carolina’s marine resources.