Dynamics of bigeye (Thunnus obesus) and yellowfin (T. albacares) tuna in Hawaii’s pelagic fisheries: analysis of tagging data with a bulk transfer model incorporating size-specific attrition

Tag release and recapture data of bigeye (Thunnus obesus) and yellowfin tuna (T. albacares) from the Hawaii Tuna Tagging Project (HTTP) were analyzed with a bulk transfer model incorporating size-specific attrition to infer population dynamics and transfer rates between various fishery components. For both species, the transfer rate estimates from the offshore handline fishery areas to the longline fishery area were higher than the estimates of transfer from those same areas into the inshore fishery areas. Natural and fishing mortality rates were estimated over three size classes: yellowfin 20–45, 46–55, and ≥56 cm and bigeye 29–55, 56–70, and ≥71 cm. For both species, the estimates of natural mortality were highest in the smallest size class. For bigeye tuna, the estimates decreased with increasing size and for yellowfin tuna there was a slight increase in the largest size class. In the Cross Seamount fishery, the fishing mortality rate of bigeye tuna was similar for all three size classes and represented roughly 12% of the gross attrition rate (includes fishing and natural mortality and emigration rates). For yellowfin tuna, fishing mortality ranged between 7% and 30%, the highest being in the medium size class. For both species, the overall attrition rate from the entire fishery area was nearly the same. However, in the specific case of the Cross Seamount fishery, the attrition rate for yellowfin tuna was roughly twice that for bigeye. This result indicates that bigeye tuna are more resident at the Seamount than yellowfin tuna, and larger bigeye tunas tend to reside longer than smaller individuals. This may result in larger fish being more vulnerable to capture in the Seamount fishery. The relatively low level of exchange between the Sea-mount and the inshore and longline fisheries suggests that the fishing activity at the Seamount need not be of great management concern for either species. However, given that the current exploitation rates are considered moderate (10–30%), and that Seamount aggregations of yellowfin and bigeye tuna are highly vulnerable to low-cost gear types, it is recommended that further increases in fishing effort for these species be monitored at Cross Seamount.

Age, growth, and mortality of the Mayan cichlid (Cichlasoma urophthalmus) from the southeastern Everglades

Mayan cichlids (Cichlasoma urophthalmus) were collected monthly from March 1996 to October 1997 with hook-and-line gear at Taylor River, Florida, an area within the Crocodile Sanctuary of Everglades National Park, where human activities such as fishing are prohibited. Fish were aged by examining thin-sectioned otoliths, and past size-at-age information was generated by using back-calculation techniques. Marginal increment analysis showed that opaque growth zones were annuli deposited between January and May. The size of age-1 fish was estimated to be 33–66 mm standard length (mean=45.5 mm) and was supported by monthly length-frequency data of young-of-year fish collected with drop traps over a seven-year period. Mayan cichlids up to seven years old were observed. Male cichlids grew slower but achieved a larger size than females. Growth was asymptotic and was modeled by the von Bertalanffy growth equation Lt=263.6(1–exp[–0.166(t–0.001)]) for males (r2=0.82, n=581) and Lt=215.6 (1–exp[–0.197(t–0.058)]) for females (r2= 0.77, n=639). Separate estimates of total annual mortality were relatively consistent (0.44–0.60) and indicated moderate mortality at higher age classes, even in the absence of fishing mortality. Our data indicated that Mayan cichlids grow slower and live longer in Florida than previously reported from native Mexican habitats. Because the growth of Mayan cichlids in Florida periodically slowed and thus produced visible annuli, it may be possible to age introduced populations of other subtropical and tropical cichlids in a similar way.

水稻中OsERD2和OsRAA1基因的功能分析

内质网中一些可溶性蛋白含有Lys-Asp-Glu-Leu（KDEL）基序作为内质网滞留的信号，这些内质网滞留蛋白可以离开内质网进入高尔基体进行糖基化修饰。目前的研究表明，KDEL基序可以被滞留蛋白受体识别，通过反向运输途径将其运回内质网。ERD2是第一个在酵母中被鉴定的内质网滞留蛋白受体。在人、拟南芥、弓形虫等生物中也鉴定出类似的内质网滞留蛋白受体。ERD2在拟南芥中的同源基因aERD2受内质网胁迫信号的诱导，在水稻中还未见该类受体的报道。 本工作从水稻中克隆到ERD2的同源基因OsERD2。OsERD2的cDNA全长为1081bp，编码一含215个氨基酸的蛋白。OsERD2与酵母、拟南芥、人中的内质网滞留蛋白受体的同源性分别为43.38%、72.56%、54.42%。疏水性分析显示该蛋白具有7个跨膜区；OsERD2呈组成型表达模式；亚细胞定位显示OsERD2主要分布于高尔基体中；利用酵母互补实验证明OsERD2可以恢复酵母erd2缺失突变体的表型。这些结果表明，OsERD2是水稻中的内质网滞留蛋白受体。 借助农杆菌介导的转化将OsERD2在水稻中超表达，分析转基因水稻对二硫苏糖醇（DTT）处理的响应。结果显示DTT处理抑制水稻幼苗生长，超表达OsERD2株系受抑制程度更为明显。表明OsERD2转基因水稻对内质网胁迫更加敏感。因此，OsERD2可能参与了水稻中的未折叠蛋白响应。 本论文还比较分析了OsRAA1/AtFPF1的一些新功能。OsRAA1（Oryza sativa root architecture associated 1）是拟南芥AtFPF1在水稻中的同源基因，参与水稻根发育的调控。我们将OsRAA1在拟南芥中异源超表达，发现OsRAA1的积累使转基因拟南芥的开花时间提前，同时发现在白光条件下转基因拟南芥的下胚轴长度增加。进一步分析表明，在蓝光、远红光和黑暗条件下转OsRAA1拟南芥下胚轴长度和野生型没有明显区别，但在红光条件下，转基因拟南芥的下胚轴长度是野生型的两倍。AtFPF1转基因拟南芥也表现出类似的表型，说明RAA1/FPF1蛋白不但可以调控拟南芥开花时间而且参与红光对下胚轴生长的光抑制过程，它们在进化过程中保留了这两个方面的功能。

The Younger Dryas and millenial-scale oceanographic variability in the Sulu Sea, tropical western Pacific

EXTRACT (SEE PDF FOR FULL ABSTRACT): A high resolution, AMS carbon-14-dated sediment record from the Sulu Sea clearly indicates the Younger Dryas climatic event affected the western equatorial Pacific. Presence of the Younger Dryas in the tropical western Pacific indicates this climatic event is not restricted to the North Atlantic nor to high latitudes, but is global in extent.

Climate-driven hydrologic transients in Holocene lake records

Understanding the link between climate and regional hydrologic processes is of primary importance in estimating the possible impact of future climate change and in the validation of climate models that attempt to simulate such changes. Two distinct problems need to be addressed: quantitatively establishing the link between changes in climate and the hydrologic cycle, and determining how these changes are expressed over differing temporal and spatial scales. To solve these problems, our interdisciplinary group is studying important aspects of hydrology, paleolimnology, geochemistry, and paleontology as they apply to climate-driven hydrologic changes.

Condition factor and length-weight relationship of Nemipterus japonicus (Bloch) off Bombay coast

Fluctuations in the K values of Nemipterus japonicus (Bloch) off Bombay coast were interpreted regarding sex, month and females maturity stage. These indicate differential growth rates in males and females. Males and females attain first maturity at 145 mm and 115 mm respectively, second maturity is attained by both the sexes at 195 mm. First spawning occurs when both are of 155 mm length and at second spawning males and females attain 215 and 205 mm of length respectively. The fish mature and breed at "O" year; the main spawning period is from August to November with peak spawning activities in October. It grows about 155 mm in first year at 12.91mm per month and about 215 mm in the second year at 5.0 mm per month on an average. Length-weight relationships for males and females are given. The rate of growth of females by weight was found to be slower below 150 mm, but faster than that of males above 150 mm specimens.

Mortality rates of the Poovalan prawn (Metapenaeus dobsoni) along the southwest coast of India with a note on the dynamics of its population

The annual instantaneous total mortality coefficient (Z) for the prawn Metapenaeus dobsoni has been estimated to range from 0.8 to 5.14 by the cumulative catch curve method. Different methods used in the study resulted in wide ranging values of natural mortality (M) (0.6 to 2.303), but the yield per recruit model when superimposed with the absolute yield values revealed the right order to be > 2. The biologically optimum yield of about 18 thousand tons is obtained for an effort of 2,702 trawlers per day for 215 fishing days when the annual exploitation ratio (E) is about 52%.