Further records of Teredicola typicus C. B. Wilson, 1942 (Cgpepoda: Cyclopoida) from shipworms in Northern New Zealand (note)

Teredicola typicus, previously recorded from Bankia australis Caiman, 1920 at two sites in the Auckland area, has been found at Bay of Islands, Whangarei, Mahurangi, and Coromandel Harbours in the North Island of New Zealand. Two specimens have also been found in another shipworm, Lyrodus pedicellatus (Quatrefages, 1849) at Coromandel, a first record from this host in New Zealand.     

First record of mosquitofish,Gambusia holbrooki,in Tasmania,Australia: Stock structure and reproductive biology

The first population of mosquitofish, Gambusia holbrooki, was discovered in a wetland area of the upper Tamar Estuary, northern Tasmania, Australia, in November 2000. We report aspects of the structure and reproductive biology of this population, based on 1567 fish collected between August 2001 and January 2002. Females dominated most catches. Maximum lengths were 48.9 and 23.6 mm standard length (SL) for females and males, respectively. Growth of the over‐wintered cohort was evident from October, when temperatures reached >19°C; growth rates in the young‐of‐season cohort from length frequency plots were 0.38 mm/ day for females and 0.19 mm/day for males. Estimated SL at 50% maturity for females (25.0 mm) and males (17.4 mm) were attained within 7 weeks of birth. Developing embryos were present from mid October and offspring from mid November; average number of stage III embryos was 55.5 (3–144). Given their rapid reproductive turnover (c. 34‐day gestation period) and resilience to broad environmental conditions, it is likely that this exotic pest will spread to other Tasmanian localities, as it has already been discovered in areas near the wetlands since the completion of this study.     

Intraspecific Interactions and Risk of Predation for Dyspanopeus sayi (Decapoda: Xanthidae) Living on Polychaete (Filograna implexa,Serpulidae) Colonies*

Abstract. Along the Atlantic coast of the United States, the mud crab Dyspanopeus sayi frequently occurs in crevices and depressions within aggregated calcareous tubes (termed “heads”) of the serpulid polychaete Filograna implexa. In New Jersey, U.S.A., waters, crab number was significantly correlated with the logarithm of worm tube colony volume. Laboratory experiments suggested that crabs compete for shelter within worm colonies. Additional laboratory experiments indicated that colony occupancy greatly decreased the risk of predation by blue crabs (Callinectes sapidus), and field tethering experiments also demonstrated that colony occupancy significantly decreased predation risk. Thus, the consequence of holding space on worm tube heads is a greatly increased probability of survival.     

Effect of dietary docosahexaenoic acid on lipogenesis and lipolysis in black sea bream, Acanthopagrus schlegeli

1 IntroductionIt is well known that varying dietary fatty acidprofile affects the tissue fatty acid composition and e-ven the growth performance in fish ( Bell et al.,2002; Figueiredo -Silva et al., 2005; Harel andPlace, 2003; Schulz et al., 2005; Tocher et al.,2003). Docosahexaenoic acid (DHA), an importantessential fatty acid for marine species, has the effectnot only on the fatty acid profile of fish body tissue,but also on biological and physiological conditions(Ishizaki et al., 2000; …     

Nesting ecology and hatching success of the hawksbill turtle (2004–2014) on Cousine Island,Seychelles

Populations of the Critically Endangered hawksbill turtle Eretmochelys imbricata in the Seychelles showed significant declines in the past. They have since recovered and nesting numbers are increasing because of increased protection and management intervention. Data on their nesting ecology on Cousine Island were collected and analysed for the breeding seasons from 2004/2005 to 2013/2014 with the aim of improving management methods. The findings indicate that the number of nesting individuals increased during the study period (from x? = 34.3 nesters between 2004 and 2009, to x? = 55.4 nesters between 2010 and 2014); however, the clutch frequency was relatively low compared with other study areas. Night-time nesting increased, most likely because of increased disturbances across the study period. Clutch sizes decreased significantly across the nesting season, and there was a significant drop in hatching success in clutch sizes exceeding 200 eggs. The predation rate and infertility rate each showed an increasing trend over time. Nests incubating in full sun showed the highest mean hatching success rate and had the shortest mean incubation duration. The present study provides insight into the species’ nesting ecology on Cousine Island and will better inform management decisions aimed at increasing hatching success and minimising threats such as beach erosion and predation.     

Albatross predation of juvenile southern blue whiting (Micromesistius australis) on the Campbell Plateau

Dietary samples collected at Campbell Island in summer 1997 indicate that southern blue whiting (Micromesistius australis) formed the bulk of the food of black‐browed albatrosses (Diomedea melanophrys impavida) during the chick‐rearing period. Birds preyed upon a single size class of fish with a mode at 80–90 mm standard length; fish were 4–5 months old and belonged to the 0+ age group. Satellite tracking showed that, when performing trips of short duration, adult albatrosses foraged within the 1000 m depth contour in the subantarctic zone north of Campbell Island. The feeding ecology of albatrosses thus suggests that juvenile (0+) southern blue whiting are pelagic and occur in dense schools in the top 5 m of the water column over the Campbell Plateau during the summer months. The high reliance of birds on juvenile southern blue whiting during the chick‐rearing period has implications for the management of the southern blue whiting fishery and the conservation of black‐browed albatrosses and other marine predators occurring in the New Zealand subantarctic area.     

Sources and threats of chronic tissue loss on coral reefs in the Lakshadweep Islands,Indian Ocean

Tissue degradation and resulting mortality are major threats to coral reefs around the world. Information on interactions of the major environmental factors that mediate tissue loss and mortality in coral reefs is of great importance. It is essential to understand the prevailing reef health conditions and to develop appropriate management actions. In the present study, a series of benthic surveys conducted in the Lakshadweep Islands revealed the interaction of major biological factors in causing tissue loss and mortality. Hierarchical regression analysis revealed interactions of various environmental scenarios. Tissue loss was prevalent in islands with high cover of massive corals (m = 20.91) and low in islands dominated by branching corals (m = 0.61). Hierarchical regression analysis revealed black band disease (β = .59; p < .001) and algal interactions (β = .48; p < .001) to be major factors responsible for coral mortality caused by tissue loss in the region.     

Effects of sodium cyanide (nacn) on the endogenous rhythm of the oxygen consumption rate in the black rockfishsebastes schlegeli

Laboratory bioassays were conducted to test the acute toxicity effects of sudden exposure to sodium cyanide (NaCN) on the endogenous rhythm of the oxygen consumption rate (OCR) in the black rockfishSebastes schlegeli. The OCR of the black rockfish (n = 14, total length = 20.4 ± 1.16 cm, wet weight = 158 ± 25 g) was measured with an automatic intermittentflow-respirometer. OCR decreased significantly when experimental fish were exposed to NaCN. When exposed to 10 ppb NaCN, fish were able to recover their OCR rhythmic activities. When fish were exposed to 20 ppb, however, the metabolic activity rhythms were not recovered. These results suggest that exposure to NaCN concentrations over 20 ppb cause severe physiological damage to the endogenous rhythms of black rockfish.     

温度对条石鲷幼鱼代谢率、排泄率及窒息点的影响

采用静水密闭式呼吸仪,分别测定了13,18,23,28和33℃5个水温梯度下条石鲷Oplegnat-hus fasciatus幼鱼的代谢率、排泄率及窒息点。结果表明:(1)不同温度条件下,条石鲷幼鱼的代谢率和排泄率差异显著(p<0.05);当温度由13℃升高至28℃时,条石鲷幼鱼的代谢率和排泄率均随之升高;当水温为28℃时,其代谢率和排泄率达最大值,分别为(16.33±0.45)J/(g·h)和(1.03±0.04)J/(g·h),是13℃实验组的6.69倍和5.15倍;与28℃实验组相比,33℃实验组的代谢率和排泄率分别降低了19.04%和15.53%,33℃已超出了条石鲷幼鱼生长的最高适温。(2)实验温度下,条石鲷幼鱼的蛋白质供能比值为37.94%～72.24%,蛋白质是其主要能源物质。(3)条石鲷幼鱼的窒息点为(3.17～3.64)mg/L,并随水温升高而升高。(4)Q10值和蛋白质供能比值的变化特征表明,18～28℃是条石鲷幼鱼的适宜生长温度。     

西沙群岛永兴岛礁坡石珊瑚覆盖率的空间变化

连续影像样方调查方法较常用的截线样条法具有空间分辨率高的特点.采用该方法于2008年7月在西沙群岛永兴岛礁坡开展了5条垂直岸线断面和2条平行岸线断面的石珊瑚覆盖率调查.调查发现,永兴岛珊瑚覆盖率存在显著的空间差异,北、西北和东部断面珊瑚分布相对较多,覆盖率较高;西和西南部断面珊瑚分布稀少,覆盖率低.其中北、西北和东部断面沿礁坡方向珊瑚分布明显减少,礁坡中上部30-50m以上、水深5-6m以浅的区域,珊瑚覆盖率高;而礁坡中下部50m以下、水深约6m以深区域,珊瑚分布少,覆盖率低.此外,北和西北部断面还发现由棘冠海星Acanthaster planci和黑皮海绵Terpios hoshinota分别造成的珊瑚白化和珊瑚黑死现象,一定程度上降低了珊瑚覆盖率.永兴岛珊瑚覆盖率的下降以及空间变化格局的形成主要与30年以来日益增加的人类活动和珊瑚礁区过度开发有关.     

Impacts of human interventions on the seasonal and nodal dynamics of the M2 and K1 tidal constituents in Lingdingyang Bay of the Zhujiang River Delta,China

Natural and human-induced changes may exert considerable impacts on the seasonal and nodal dynamics of M₂ and K₁ tidal constituents. Therefore, quantifying the influences of these factors on tidal regime changes is essential for sustainable water resources management in coastal environments. In this study, the enhanced harmonic analysis was applied to extract the seasonal variability of the M₂ and K₁ tidal amplitudes and phases at three gauging stations along Lingdingyang Bay of the Zhujiang River Delta. The seasonal dynamics in terms of tidal wave celerity and amplification/damping rate were used to quantify the impacts of human-induced estuarine morphological alterations on M₂ and K₁ tidal hydrodynamics in inner and outer Lingdingyang Bay. The results show that both tidal amplification/damping rate and wave celerity were considerably increased from the pre-anthropogenic activity period (Pre-AAP) to the post-anthropogenic activity period (Post-AAP) excepting the tidal amplification/damping rate in outer Lingdingyang Bay, and the variations in outer Lingdingyang Bay was larger than those in inner Lingdingyang Bay. The alterations in these two parameters were more significant in flood season than in dry season in both inner and outer Lingdingyang Bay. The seasonal variability of M₂ and K₁ tidal amplitudes were further quantified using a regression model accounting for the 18.61-year lunar nodal modulation, where this study observes a considerable alteration in M₂ constituent owing to human interventions. During the Post-AAP, the M₂ amplitudes at the downstream station were larger than those that would have occurred in the absence of strong human interventions, whereas the opposite was true for the upstream station, leading to a substantial decrease in tidal amplification in outer Lingdingyang Bay. However, it is opposite in inner Lingdingyang Bay. The underlying mechanism can be primarily attributed to channel deepening and narrowing caused by human interventions, that resulted in substantial enlargement of the bay volume and reduced the effective bottom friction, leading to faster wave celerity and stronger amplified waves.