Dispersion and feeding of larval herring (Clupea harengus L.) in the Moray Firth during September 1985

A plume of herring larvae dispersing from a spawning site at Clythness in the Moray Firth (northern Scotland) was surveyed during early September 1985. Several cohorts of larvae were evident from the length distributions, and these were arranged in order of increasing length (age) towards the south-west. The spacing of cohort centres indicated a drift rate of 1–2 km day⁻¹.Calanoid copepod nauplii constituted the major proportion of the diet of larvae <10 mm sampled during the study. Cyclopoid copepod nauplii and gastropod veligers were not found in the diet although they were present in the water. The distribution of nauplii in the region was inversely correlated with the concentration of phytoplankton chlorophyll, and nauplii concentrations were above average in the vicinity of the herring spawning site. The drift trajectory of the herring larvae took them towards an area of high copepodite and adult copepod concentration—items which formed an increasing part of the diet of larger (older) larvae.     

Spawning patterns of four species of predominantly temperate pelagic fishes in the sub-tropical waters of southern Queensland

The diverse pelagic fish assemblage of sub-tropical southern Queensland includes fishes with predominantly temperate distributions, such as tailor Pomatomus saltatrix, sardine Sardinops sagax, round herring Etrumeus teres, and Australian anchovy Engraulis australis. The peak spawning seasons of P. saltatrix, S. sagax and E. teres occur during late winter and early spring (June–October). Eggs and larvae of these three species are widely distributed in shelf waters and comprise >50% of the ichthyoplankton assemblage during this period. Mean monthly sea surface temperatures (SSTs) during late winter and early spring range from 21 to 23 °C, and are thus similar to those recorded in southern Australia during summer and autumn, which is the spawning season of these three species in those temperate waters. E. australis eggs occur mainly in inshore waters, and comprise >50% of fish eggs collected during summer and autumn when mean monthly SSTs in southern Queensland exceed 27 °C. E. australis also spawns mainly during summer and autumn in temperate Australia. Hence, water temperature may be less important as a determinant of the spawning season of E. australis than it is for the other three species. The suitability of southern Queensland for spawning by predominantly temperate species during late winter and early spring may contribute to the high diversity of the region's pelagic fish assemblage. Adult P. saltatrix, S. sagax and E. teres appear to migrate northwards into southern Queensland during early winter to spawn, and larvae may be transported southwards into temperate waters by the East Australian Current. This dispersal-migration pattern is similar to those observed for several species, including P. saltatrix, in the western boundary current systems off the east coasts of North America and Africa. Hence, pelagic fishes in ecosystems off the east coast of three continents migrate into sub-tropical waters to spawn, and larvae are transported back into temperate nursery areas by the prevailing current.     

不同浓度的KCI对海湾扇贝眼点幼虫附着变态作用的研究

本文在有附着基的条件下进行KCI溶液对海湾扇贝眼点幼虫的附着变态研究，并观察春成活情况。结果表明：KCI对眼点幼虫的诱导效应随KCI浓度和作用时间的增大而增大，但过高则抑制眼点幼虫的附着变态,而成活率则随浓度增加和处理时间延长而降低，其中30mmol/L效果最好。并进行了小型生产试验，效果较好。     

核电站温排水对大亚湾鲷科鱼卵、仔鱼分布的影响

在广东大亚湾核电站温排水排放前、后，自１９９３年１月２０日至１９９５年２月２８日对该站附近水域１４个站位共进行６个航次的采样调查，收集鲷科鱼卵、仔鱼样本和同一站位的水温资料。结果表明，各站位的绸科鱼卵、仔鱼的分布在温排水排放前、后与水温变化密切相关。水域升温２—８℃对鲷科鱼类的产卵、孵化和仔鱼生长发育有明显的影响。鉴于目前升温水域范围只限在２ｎｍｉｌｅ内，可以认为整个大亚湾鲷科鱼类的资源和补充尚未受到较大的影响。     

The distribution of brachyuran crustacean megalopae in the waters of the York river, lower Chesapeake Bay and adjacent shelf: Implications for recruitment

Vertical and horizontal distributions are described for megalopae of 11 brachyuran taxa common to the lower Chesapeake Bay and adjacent shelf. Three distribution patterns are apparent from horizontal distribution.

1. (1) More than 75% of the megalopae of estuarine adults, such as Hexapanopeus angustifrons, Neopanope sayi, Panopeus herbstii, Rhithropanopeus harrisii and Pinnotheres ostreum, are retained in estuarine waters.

2. (2) The megalopae of three estuarine taxa, Callinectes sapidus, Uca spp. and Pinnixa sp., are most abundant on the shelf.

3. (3) More than 90% of the megalopae of the shelf species, Portunus sp., Cancer irroratus and Libinia spp. remained in shelf waters.

Vertical distributions indicate the megalopae of a majority of estuarine crabs are epibenthic when waters are stratified. Exceptions include the megalopae of both Rhithropanopeus which are found slightly shallower in well mixed waters and Callinectes sapidus which are generally most abundant in the neuston. The megalopae of two shelf species, Portunus sp. and Cancer irroratus, reach highest densities in surface waters, while those of Libinia spp. are common in the epibenthos.Megalopal distributions analyzed with respect to water column stratification show megalopae never reached highest densities within the layer of the pycnocline. The megalopae of five species show significant shifts in vertical distributions between stratified and homogeneous water columns.     

Larval Stages and Balanus (Cim'pedia) Settlement in a Port Environment with a Key to Naupliar Stages of Tyrrhenian Species

Abstract. .Some observations on larval life and barnacle settlement in the Port of Genoa are reported together with a key of the nauplii of the four species recorded in the Tyrrhenian coasts: Balanus amphiuite, Balanus perforatus, Balanus trigonus and Balanus eburneus. Weekly densities of naupliar stages for each species as well as the average percent reduction from one stage to the next until the cypris stage have been recorded. The amount of the latter is recorded both in plankton and along with settled barnacles on artificial substrata.