Tropical Marine Species Research Articles

Development of an integrated multi-trophic aquaculture (IMTA) system for tropical marine species in southern cebu, Central Philippines

This study presents the establishment of an integrated multi-trophic aquaculture (IMTA) system in the tropical open waters of southern Cebu, Philippines using a combination of locally available species, namely donkey’s ear abalone (Haliotis asinina) as fed species and seaweeds (Gracilaria heteroclada and Eucheuma denticulatum) as inorganic extractive species. The culture of Caulerpa lentillifera as a biofilter did not work in the open sea cultivation system using baskets. Monthly measurements of shell length, width and body weight of the cultured abalones, together with in situ measurements of physicochemical parameters to assess any changes in water quality, mainly nitrate, nitrite, ammonia and phosphate, were conducted over a year period from February 2013 to January 2014 in three designated stations (Abalone, Seaweed and Control Stations) at three different depths (surface, middle and bottom).Cage culture of abalone side by side with seaweeds in the open sea did not result in any significant water quality disturbance in the area—at least not in the current volume of caged abalones being used. Of the four inorganic compounds monitored in the field, nitrate and ammonia in the Seaweed Station were shown to have relatively lower year-round average values when compared with the Abalone Station, although in the case of nitrate, it was higher in the Control Station compared with the abalone and Seaweed Stations. Although this difference was not significant, it shows the red seaweeds, G. heteroclada and E. denticulatum, to be functioning as a natural filter for these two nutrients. In contrast, nitrite, and phosphate concentrations were not reduced indicating that the seaweeds were not effective biofilter for these two nutrients.The two-month old hatchery-bred donkey’s ear abalones can grow to a size of 53.8×28.2mm (L×W) and body weight of 37.8g after a period of 12 months. Any expansion of the farm into a much larger commercial-scale farm will have to be complimented with seaweeds stocked around it if only to mitigate possible build-up of excess inorganic wastes—to serve as both a natural filter and as a source of natural feed. The potential use of an organic extractive species has to be further studied under farm condition to achieve its full potential as an IMTA species.

Differential bioaccumulation of 134Cs in tropical marine organisms and the relative importance of exposure pathways

Bioaccumulation of 134Cs was determined in 5 tropical marine species: three bivalves (the oysters Isognomon isognomum and Malleus regula, and the clam Gafrarium pectinatum), one decapod (shrimp Penaeus stylirostris) and one alga (Lobophora variegata). Marine organisms were exposed to the radionuclides via different pathways: seawater (all of them), food (shrimp and bivalves) and sediment (bivalves). Our results indicate that the studied tropical species accumulate Cs similarly than species from temperate regions whereas retention capacities seems to be greater in the tropical species. Bioaccumulation capacities of the two oysters were similar for all the exposure pathways. The alga, and to a lesser extent the shrimp, concentrated dissolved Cs more efficiently than the bivalves (approx. 14 and 7 times higher, respectively). Assimilation efficiencies of Cs in bivalves and shrimp after a single feeding with radiolabelled food were comprised between 7.0 ± 0.4 and 40.7 ± 4.3%, with a variable retention time (half-life –Tb1/2– ranging from 16 ± 3 to 89 ± 55 d). Although the clam lives buried in the sediment, this exposure pathway resulted in low bioaccumulation efficiency for sediment-bound Cs (mean transfer factor: 0.020 ± 0.001) that was lower than the two oyster species, which are not used to live in this media (0.084 ± 0.003 and 0.080 ± 0.005). Nonetheless, Cs accumulated from sediment was similarly absorbed (61.6 ± 9.7 to 79.2 ± 2.3%) and retained (Tb1/2: 37 ± 2 to 58 ± 25 d) for the three bivalves species. Despite the poor transfer efficiency of Cs from food, the use of a global bioaccumulation model indicated that the trophic pathways was the main uptake route of Cs in the bivalves and shrimp. In shelled organisms, shells played a non-negligible role in Cs uptake, and their composition and structure might play a major role in this process. Indeed, most of the Cs taken up from seawater and sediment was principally located on the hard parts of the bivalves and shrimp, with the exception of G. pectinatum, where Cs was mainly distributed in the soft-parts.

Range extensions for heterobranch sea slugs (formerly opisthobranch) belonging to the families Diaphanidae, Plakobranchidae and Facelinidae on the eastern coast of Australia – CORRIGENDUM

Southern range extensions of the tropical Australian heterobranch sea slug fauna may be symptomatic of climate change, particularly in south-eastern Australia, a recognized climate change hot-spot. In the Solitary Islands Marine Park, northern New South Wales, the presence of biogeographic mixing means that the southern coastal distribution limit of several tropical marine species and the northern limit of some temperate species overlap. During a year-long series of monthly surveys of sea slug communities on intertidal rocky shores, we observed four species beyond their previously recorded range – Colpodaspis thompsoni, Elysia pusilla, Phidiana bourailli and Herviella claror. The southern migration of species is an anticipated response to warming seas and we note an apparent extension of the southern limit for these taxa.

Range extensions for heterobranch sea slugs (formerly opisthobranch) belonging to the families Diaphanidae, Plakobranchidae and Facelinidae on the eastern coast of Australia

Southern range extensions of the tropical Australian heterobranch sea slug fauna may be symptomatic of climate change, particularly in south-eastern Australia, a recognized climate change hot-spot. In the Solitary Islands Marine Park, northern New South Wales, the presence of biogeographic mixing means that the southern coastal distribution limit of several tropical marine species and the northern limit of some temperate species overlap. During a year-long series of monthly surveys of sea slug communities on intertidal rocky shores, we observed four species beyond their previously recorded range –Colpodaspis thompsoni, Elysia pusilla, Phidiana bourailliandHerviella claror. The southern migration of species is an anticipated response to warming seas and we note an apparent extension of the southern limit for these taxa.

Larval dispersal and movement patterns of coral reef fishes, and implications for marine reserve network design.

Well-designed and effectively managed networks of marine reserves can be effective tools for both fisheries management and biodiversity conservation. Connectivity, the demographic linking of local populations through the dispersal of individuals as larvae, juveniles or adults, is a key ecological factor to consider in marine reserve design, since it has important implications for the persistence of metapopulations and their recovery from disturbance. For marine reserves to protect biodiversity and enhance populations of species in fished areas, they must be able to sustain focal species (particularly fishery species) within their boundaries, and be spaced such that they can function as mutually replenishing networks whilst providing recruitment subsidies to fished areas. Thus the configuration (size, spacing and location) of individual reserves within a network should be informed by larval dispersal and movement patterns of the species for which protection is required. In the past, empirical data regarding larval dispersal and movement patterns of adults and juveniles of many tropical marine species have been unavailable or inaccessible to practitioners responsible for marine reserve design. Recent empirical studies using new technologies have also provided fresh insights into movement patterns of many species and redefined our understanding of connectivity among populations through larval dispersal. Our review of movement patterns of 34 families (210 species) of coral reef fishes demonstrates that movement patterns (home ranges, ontogenetic shifts and spawning migrations) vary among and within species, and are influenced by a range of factors (e.g. size, sex, behaviour, density, habitat characteristics, season, tide and time of day). Some species move <0.1-0.5 km (e.g. damselfishes, butterflyfishes and angelfishes), <0.5-3 km (e.g. most parrotfishes, goatfishes and surgeonfishes) or 3-10 km (e.g. large parrotfishes and wrasses), while others move tens to hundreds (e.g. some groupers, emperors, snappers and jacks) or thousands of kilometres (e.g. some sharks and tuna). Larval dispersal distances tend to be <5-15 km, and self-recruitment is common. Synthesising this information allows us, for the first time, to provide species, specific advice on the size, spacing and location of marine reserves in tropical marine ecosystems to maximise benefits for conservation and fisheries management for a range of taxa. We recommend that: (i) marine reserves should be more than twice the size of the home range of focal species (in all directions), thus marine reserves of various sizes will be required depending on which species require protection, how far they move, and if other effective protection is in place outside reserves; (ii) reserve spacing should be <15 km, with smaller reserves spaced more closely; and (iii) marine reserves should include habitats that are critical to the life history of focal species (e.g. home ranges, nursery grounds, migration corridors and spawning aggregations), and be located to accommodate movement patterns among these. We also provide practical advice for practitioners on how to use this information to design, evaluate and monitor the effectiveness of marine reserve networks within broader ecological, socioeconomic and management contexts.

Effects of Cd, Co, Cu, Ni and Zn on asexual reproduction and early development of the tropical sea anemone Aiptasia pulchella.

Currently few studies present sub-lethal toxicity data for tropical marine species, and there are no routine toxicity tests using marine cnidarians. The symbiotic sea anemone Aiptasia pulchella has been identified as a useful species for ecotoxicological risk assessment, and would provide a tropical marine cnidarian representative. Chronic sub-lethal toxicity tests assessing the effects of 28-day trace metal exposure on asexual reproduction in A. pulchella were investigated, and concentration-dependant reductions in the number of offspring that were produced were evident for all metal exposures. Metal concentration estimates causing 50% reductions in the numbers of asexually-reproduced juveniles after 28-day exposures (28-day effect concentrations 50%: EC50s) were 14 µg/L for copper, 63 µg/L for zinc, 107 µg/L for cobalt, 145 µg/L for cadmium, and 369 µg/L for nickel. Slightly higher 28-day EC50s of 16 µg/L for copper, 192 µg/L for zinc, 172 µg/L for cobalt, 185 µg/L for cadmium, and 404 µg/L for nickel exposures and were estimated based on reductions in the total number of live developed and undeveloped offspring. These sensitive and chronic sub-lethal toxicity estimates help fill the knowledge gap related to metal effects on cnidarians over longer exposure periods, and this newly-developed bioassay may provide a much needed tool for ecotoxicological risk assessment relevant to tropical marine environments.

Evolutionary dynamics in the southwest Indian ocean marine biodiversity hotspot: a perspective from the rocky shore gastropod genus Nerita.

The Southwest Indian Ocean (SWIO) is a striking marine biodiversity hotspot. Coral reefs in this region host a high proportion of endemics compared to total species richness and they are particularly threatened by human activities. The island archipelagos with their diverse marine habitats constitute a natural laboratory for studying diversification processes. Rocky shores in the SWIO region have remained understudied. This habitat presents a high diversity of molluscs, in particular gastropods. To explore the role of climatic and geological factors in lineage diversification within the genus Nerita, we constructed a new phylogeny with an associated chronogram from two mitochondrial genes [cytochrome oxidase sub-unit 1 and 16S rRNA], combining previously published and new data from eight species sampled throughout the region. All species from the SWIO originated less than 20 Ma ago, their closest extant relatives living in the Indo-Australian Archipelago (IAA). Furthermore, the SWIO clades within species with Indo-Pacific distribution ranges are quite recent, less than 5 Ma. These results suggest that the regional diversification of Nerita is closely linked to tectonic events in the SWIO region. The Reunion mantle plume head reached Earth’s surface 67 Ma and has been stable and active since then, generating island archipelagos, some of which are partly below sea level today. Since the Miocene, sea-level fluctuations have intermittently created new rocky shore habitats. These represent ephemeral stepping-stones, which have likely facilitated repeated colonization by intertidal gastropods, like Nerita populations from the IAA, leading to allopatric speciation. This highlights the importance of taking into account past climatic and geological factors when studying diversification of highly dispersive tropical marine species. It also underlines the unique history of the marine biodiversity of the SWIO region.

Development of a chronic, early life-stage sub-lethal toxicity test and recovery assessment for the tropical zooxanthellate sea anemone Aiptasia pulchella

There is an urgent need to identify additional tropical marine species and develop sensitive sub-lethal and chronic toxicity test methods for routine ecotoxicology. The tropical symbiotic sea anemone Aiptasia pulchella is a suitable species for use in ecotoxicology and here we have assessed the effects of trace metal exposures on the development of asexually produced A. pulchella pedal lacerates to a juvenile stage. Concentrations of 55µg/L for cadmium, 262µg/L for cobalt, 5µg/L for copper, and 269µg/L for zinc were estimated to inhibit normal development by 50 percent after 8-d exposures, and are among the most sensitive available toxicity estimates for marine organisms. This work illustrates the potential value of this species and sub-lethal toxicological endpoint for routine ecotoxicology in tropical marine environments.

Acute toxicity testing with the tropical marine copepod Acartia sinjiensis: Optimisation and application

Globally there is limited toxicity data for tropical marine species, and there has been a call for further research and development in the area of tropical marine ecotoxicology. An increase in developmental pressures in northern tropical Australia is causing a higher demand for toxicity test protocols with ecologically relevant species. Copepods are a diverse group of zooplankton that are major components of marine food webs. The calanoid copepod Acartia sinjiensis is widely distributed across tropical and sub-tropical brackish to marine waters of Australia and was identified in a recent comprehensive review of marine tropical toxicity testing in Australia as a suitable test organism. Through a number of optimisation steps including feeding trials, changes to culture and test conditions; a 48-h acute toxicity test with A. sinjiensis was modified to become a highly reliable and reproducible standard test protocol. Control mobility was improved significantly, and the sensitivity of A. sinjiensis to copper (EC50 of 33µg/L), ammonia (EC50 of 10mg/L) and phenol (EC50 of 13mg/L) fell within the ranges of those reported previously, indicating that the modifications did not alter its sensitivity. In a comprehensive literature search we found that this species was the most sensitive to copper out of a range of marine copepods. The test was also successfully applied in toxicity assessments of four environmental samples: two produced formations waters (PFWs) and two mine tailing liquors (MTLs). The toxicity assessments utilised toxicity data from a suite of marine organisms (bacteria, microalgae, copepods, sea urchins, oysters, prawns, and fish). For the PFWs, which were predominantly contaminated with organic chemicals, A. sinjiensis was the most sensitive species (EC50 value 2–17 times lower than for any other test species). For the predominantly metal-contaminated mine tailing liquors, its sensitivity was similar to that of other test species used. The modified 48-h acute toxicity test with A. sinjiensis proved to be a valuable tool in these toxicity assessments, and is recommended for use in tropical marine toxicity assessments for northern Australia.

Aiptasia pulchella: a tropical cnidarian representative for laboratory ecotoxicological research

An urgent need exists to identify suitable tropical marine species for use in the development of sensitive and reliable test methods for routine laboratory ecotoxicological testing. Corals are a group of organisms not represented in routine ecotoxicology due to inherent difficulties in laboratory husbandry, and sea anemones from the same phylum (cnidaria) may be useful proxies. Aiptasia pulchella is a tropical symbiotic sea anemone with a wide geographic range. It is well suited to laboratory conditions and has been used extensively in research. However, its suitability as a toxicity test species has not been investigated. Assessment of juvenile recruitment in laboratory and semi-outdoor conditions showed higher production in semi-outdoor conditions; however, laboratory rearing produced enough recruits to run routine toxicity tests. In investigations of the sensitivity of A. pulchella to contaminants, acute tests were conducted on 1- to 2-mm juveniles using copper. Lethal concentration, 50% (LC50) values at 96 h estimated from tests using five and 10 replicates ranged from 30 to 83 and 60 to 90 µg/L, respectively, and a 28-d LC50 of 26 µg/L was estimated. During the present study, sublethal endpoints were investigated; chronic assessment of inhibited asexual reproduction looks promising (12-d effective concentration, 50% [EC50] 15 µg/L) and should be assessed further. Aiptasia pulchella is a species worthy of investigation as a cnidarian representative, and will be an invaluable contribution to tropical marine ecotoxicologists.

Trans-Atlantic rafting by the brooding reef coral Favia fragum on man-made flotsam

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 445:209-218 (2012) - DOI: https://doi.org/10.3354/meps09460 Trans-Atlantic rafting by the brooding reef coral Favia fragum on man-made flotsam Bert W. Hoeksema1,* Piet J. Roos2,4 Gerhard C. Cadée3 Department of Marine Zoology, Netherlands Centre for Biodiversity Naturalis, PO Box 9517, 2300 RA Leiden, The Netherlands 2Netherlands Centre for Biodiversity Naturalis (Section ZMA), University of Amsterdam, PO Box 94766, 1090 GT Amsterdam, The Netherlands 3Royal Netherlands Institute for Sea Research, PO Box 59, 1790 AB Den Burg, Texel, The Netherlands 4Present address: Rembrandt van Rijnweg 8, 1191 GG Ouderkerk aan de Amstel, The Netherlands *Email: bert.hoeksema@ncbnaturalis.nl ABSTRACT: Specimens of the brooding reef coral Favia fragum were found on man-made flotsam stranded on the North Sea shore of the Netherlands. Based on the associated epifauna originating from the southeast USA, we estimate that the corals must have crossed the Atlantic Ocean, transported by the Gulf Stream and the North Atlantic Drift. The size of the corals suggests that they might have had enough time to cross the Atlantic alive and that they already reached the age of possible self-fertilization before they entered waters that were too cold to survive. The temperature requirements and the presently known geographic range of F. fragum are compared with Atlantic summer and winter isotherms and oceanic currents in order to project a hypothetical northernmost range boundary. With increasing pollution, man-made flotsam may become a progressively more common substrate for reef corals that depend on rafting for long-distance dispersal. Eventually, with warming seawater, floating debris may cause tropical marine species to expand their distribution ranges towards higher latitudes. KEY WORDS: Distribution range · Epifauna · Life history · Long-distance dispersal · Ocean currents · Temperature tolerance Full text in pdf format Corrigendum PreviousNextCite this article as: Hoeksema BW, Roos PJ, Cadée GC (2012) Trans-Atlantic rafting by the brooding reef coral Favia fragum on man-made flotsam. Mar Ecol Prog Ser 445:209-218. https://doi.org/10.3354/meps09460 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 445. Online publication date: January 20, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.

Speciation in tropical seas: Allopatry followed by range change

We investigated whether present distribution ranges in marine organisms are reliable indicators of the geographic pattern of past speciation events by assessing the level of geographic overlap (sympatric index) as a function of node age in four phylogenies of tropical marine species groups. The analyses led to remarkably similar results among the four groups examined with (1) most nodes associated with a sympatry index of either 0 (allopatry) or 1 (entire overlap) and (2) statistical support that sister species have an allopatric distribution significantly more frequently than sister clades (i.e. groups of species). Species divergences were expressed on a time scale and very similar times were needed for species range overlap to occur since sharp transitions from allopatry to sympatry occurred around 4Ma in all groups. Present results supports that species range changes were not random as previous simulations results supports that species range probably evolve through occasional shifts of large amplitude. In front of the time needed for species range overlapping, our study suggests that species interaction and competitive exclusion can no longer be excluded as a driver of marine species distribution.

Strategies for the capture and transport of bonefish,Albula vulpes, from tidal creeks to a marine research laboratory for long-term holding

Throughout their circumtropical distribution, bone¢sh (Albula spp.) play a vital role in local economies as a highly prized sport ¢sh. Recent interest in stock enhancement to sustain bone¢sh ¢sheries has led to the recognition that there currently are no data on how to live capture large numbers of adults (potential broodstock), transport them to captive facilities and how to handle them to ensure high survival. The objective of this study was to develop strategies for the capture and relocation of wild bone¢sh to a marine research holding facility to enable basic research and explore the potential for culturing bone¢sh for stock enhancement. Bone¢sh Albula vulpes (Linnaeus,1758) were captured as they entered or left tidal creeks on Eleuthera, The Bahamas using seine nets and then transported by boat or truck to the laboratory. The relocation process evoked secondary stress responses at the metabolic, osmoregulatory and haematological levels as indicated by changes in blood glucose, lactate, haematocrit and ion values, relative to control ¢sh. Physical and behavioural disturbances were also observed in bone¢sh that were unable to acclimate to laboratory conditions. Successful laboratory acclimation and long-term holding of wild bone¢sh was achieved through an adaptive learning process, whereby we identi¢ed a series of strategies and handling techniques to facilitate the acclimation of wild adult bone¢sh to captivity. This knowledge will enable future laboratory research on bone¢sh and is a prerequisite to the culture of this highly prized sport ¢sh, and other sub-tropical and tropical marine species.

Distribution of zooxanthellate zoanthid species (Zoantharia: ANthozoa: Hexacorallia) in southern Japan limited by cold temperatures

The distribution of several zooxanthellate zoanthid species (Hexacorallia: Anthozoa) from the genera Palythoa, Zoanthus, and Isaurus in the oceans surrounding Japan are generally now well documented, but no examination of potential environmental factors limiting their distribution has been conducted until now. Here, using distribution data from previous works as well as ocean and air temperature data, we examined the minimum ocean temperature threshold for these zoanthid species' existence, as well as what winter air temperatures limit intertidal distribution of zoanthids. Our results show that in the Japan region zooxanthellate zoanthids are limited to oceans with winter temperatures above approximately 16°C. Additionally, intertidal colonies of zooxanthellate zoanthids were not found in locations where air temperatures dropped below 8°C. Thus, as with zooxanthellate scleractinian corals, zooxanthellate zoanthid species ranges are strictly limited by minimum ocean (overall range) and air (intertidal distribution) temperatures. Utilizing these threshold data, an examination of the potential ranges of Palythoa, Zoanthus and Isaurus on a global scale shows that it is very likely Atlantic and Indo-Pacific species are isolated from each other, as previously seen with zooxanthellate corals. Additionally, the documented northern Japanese ranges of intertidal occurrences as well as overall distribution northern limits will provide valuable baseline data for future surveys to help ascertain whether tropical and sub-tropical marine species are “invading” northwards in Japan due to global warming.

GOLIATH GROUPER (PISCES: SERRANIDAE) FROM THE UPPER MIOCENE URUMACO FORMATION, VENEZUELA

T he goliath grouper (family Serranidae, subfamily Epinephelinae) inhabits tropical and subtropical waters. The Epinephelinae serranids are comprised of about 159 species in 15 genera (Heemstra and Randall, 1993) and are represented in all oceans. According to Heemstra and Randall (1993) the goliath grouper Epinephelus itajara (Lichtenstein, 1822) occurs in the eastern Atlantic Ocean from Florida to Brazil, throughout the Gulf of Mexico and in the Caribbean Sea, in the western Atlantic Ocean from Senegal to the Congo, and in the eastern Pacific Ocean from the Gulf of California to Peru. The maximum size is about 250 cm total length and they can exceed 320 kg in weight. The grouper Epinephelus lanceolatus (Bloch, 1790) occurs throughout the Indo-Pacific region, from the Red Sea to Algoa Bay, South Africa, and eastward to the Hawaiian and Pitcairn Islands, and in the western Pacific Ocean from southern Japan to Australia in the south. The maximum size is about 231 cm total length (Schultz, 1966) and 400 kg in weight (Fourmanoir and Laboute, 1976). These two species are the largest serranids in the world. Sadovy and Eklund (1999) noted that males reach a maximum age of 26 and females 37 years in a population of E. itajara . Fossil specimens of Epinephelus Bloch, 1793 are known only from Caribbean Neogene otoliths (Nolf, 1976; Nolf and Stringer, 1992; Nolf and Aguilera, 1998; Stringer, 1998; Aguilera and Rodrigues de Aguilera, 1999, 2001) and from Atlantic Neogene skeletal remains (Purdy et al., 2001). In this paper we describe the first large and complete fossil neurocrania of Epinephelus itajara and associated bones obtained from the upper Miocene Urumaco Formation (upper member) of Venezuela. These specimens provide an example of a very long-lived tropical marine species, and the explanation for its present amphitropical American …

Testing the ecotoxicology of vegetable versus mineral based lubricating oils: 2. Induction of mixed function oxidase enzymes in barramundi, Lates calcarifer, a tropical fish species

An increasing number of vegetable-based oils are being developed as environmentally friendly alternatives to petroleum products. However, toxicity towards key tropical marine species has not been investigated. In this study we used laboratory-based biomarker induction experiments to compare the relative stress of a vegetable-based lubricating oil for marine 2-stroke engines with its mineral oil-based counterpart on tropical fish. The sub-lethal stress of 2-stoke outboard lubricating oils towards the fish Lates calcarifer (barramundi) was examined using liver microsomal mixed function oxidase (MFO) induction assays. This study is the first investigation into the use of this key commercial species in tropical North Queensland, Australia in stress assessment of potential hydrocarbon pollution using ethoxyresorufin O-deethylase (EROD) induction. Our results indicated that barramundi provide a wide range of inducible rates of EROD activity in response to relevant organic stressors. The vegetable- and mineral-based lubricants induced significant EROD activity at 1.0 mg kg−1 and there was no significant difference between the two oil treatments at that concentration. At increasing concentrations of 2 and 3 mg kg−1, the mineral-based lubricant resulted in slightly higher EROD activity than the vegetable-based lubricant. The EROD activity of control and treated barramundi are found to be within ranges for other species from temperate and tropical environments. These results indicate that vegetable-based lubricants may be less stressful to barramundi than their mineral counterparts at concentrations of lubricant ⩾2 mg kg−1. There is great potential for this species to be used in the biomonitoring of waterways around tropical North Queensland and SE Asia.

Temperature influences swimming speed, growth and larval duration in coral reef fish larvae

The effects of temperature on growth, pelagic larval duration (PLD) and maximum swimming speed were compared in the tropical fish marine species Amphiprion melanopus, to determine how temperature change affects these three factors critical to survival in larvae. The effects of rearing temperature (25 and 28 °C) on the length of the larval period and growth were examined in conjunction with the effects of swimming temperature (reared at 25 °C, swum at 25 and 28 °C, reared at 28 °C, swum at 25 and 28 °C) on critical swimming speed (U-crit). Larvae reared at 25 °C had a 25% longer pelagic larval duration (PLD) than larvae reared at 28 °C, 12.3 (±0.3) days compared with 9 (±0.6) days at 25 °C. To offset this effect of reduced developmental rate, growth and U-crit were measured in larvae reared at 28 and 25 °C at the same absolute age (7 days after hatching (dah)) and same developmental age (7 dah at 28 °C cf. 11 dah at 25 °C), corresponding to the day before metamorphosis. Larvae reared at 25 °C were smaller than larvae reared at 28 °C at the same absolute age (7 dah at 25 °C cf. 7 dah at 28 °C), yet larger at similar developmental age (11 dah at 25 °C cf. 7 dah at 28 °C) when weight and standard length were compared. This stage-specific size increase did not result in better performance in larvae at the same developmental age, as there was no difference in U-crit in premetamorphic larvae reared at either temperature (7 dah at 28 °C c.f 11 dah at 25 °C). However, U-crit was considerably slower in 7-day-old larvae reared at 25 °C than larvae of the same absolute age (7 dah) reared at 28 °C. Swimming temperature controls demonstrated that a change in temperature immediately prior to swimming tests did not effect swimming performance for larvae reared at either temperature. A decreased in rearing temperature resulted in longer larval durations, reduced growth rates and slower swimming development in larvae. However, the magnitude of the response of each of these traits varied considerably. As such, larvae reared at the lower temperature were a larger size at metamorphosis but had poorer relative swimming capabilities. This study highlights the importance of measuring a range of ecologically relevant traits in developing larvae to properly characterise their relative condition and performance in response to environmental change.

The Historic Biogeography of India: Isolation or Contact?

Geophysical maps depicting continental movement have consistently shown India, as it moved northward, to be located far out in the Tethys Sea. India split off from the African east coast about 148 m.y.a. From that time onward, according to almost all geophysical accounts, India was isolated from all of other continents until the early Miocene when it made contact with Eurasia. But the biological data, both fossil and Recent, indicate that this concept cannot be correct. If India had really existed as an isolated, oceanic continent for about 100 m.y., it should have developed a peculiar biota with many endemic genera and families in its terrestrial and shallow marine habitats. But there are virtually no remains of organisms indicating that India was isolated for any substantial time (millions of years). Instead, we find that almost all Indian taxa were possessed in common with other continents. As time went on, the northern relationships became stronger and the southern ones weaker. Most of the recent geophysical accounts show India not making contact with Eurasia until the early Miocene, but fossil materials show that this event must have taken place by the early Eocene. It has been postulated that, as India moved northward, it created a biogeographic barrier that separated marine fish populations and resulted in the east-west provinces that are now apparent in the Indian Ocean. At the same time, the barrier effect was supposed to have resulted in the formation of sister species that are now located far apart. Information currently available indicates that most living, tropical marine species are probably not over 3 m.y. old. Consequently, the northward movement of India, which took place primarily between 148 and 50 m.y.a., could have no bearing on the relationships of modern species.

Interoceanic differences in adaptation: effects of history and productivity

Previously published evidence indicated that the degree of habitat specialization and enemy-related adaptation among shallow-water tropical marine species was greatest in the Indo-WestPacific (IWP), intermediate in the Eastern Pacific (EP), and lowest in the Western Atlantic (WA) and Eastern Atlantic (EA). New data on the incidence of unsuccessful shell breakage (measured a s the frequency of shell repair) and on the importance of shell breakage as a cause of death for shallow-water gastropods complicate, but do not invalidate, this picture. Columbellid and planaxid gastropods conforn~ to the expected interoceanic pattern of shell repair in that the lowest frequencies of repair were found in the Atlantic; but the Cerithiidae and Thaididae showed no interoceanic differences in repalr, and the Conidae exhibited a contradictory pattern in which repair was most frequent in the WA and least frequent in the IWP. Great intraregional variation existed in the contribution that breakage made to overall gastropod mortality, as inferred from analyses of dead shells. There was a tendency for breakage to be relatively more important as a cause of death in the IMrP and EP than in the WA, but the differences were not statistically significant. A review of other recent literature generally supported the hypothesis that the IWP biotas have undergone more specialization with respect to hab~ ta t and eneinyrelated adaptation than have marine biotas in tropical America. Available historical evidence suggests that these d~fferences are attributable to contrasting geological histories. In the IWP, extensive speciation, especially among well-armored molluscs, took place in the absence of significant extinctions. In the WA, widespread extinctions selectively eliminated armored gastropod taxa, which were not replaced through diversification of Pliocene and Pleistocene survivors. The apparent decline of planktonic productivity in many parts of the WA following uplift of the Central American land bridge during the Pliocene may have contributed to the observed pattern of molluscan extinctions. In the EP, where productivitv has remained h ~ g h , extinction rates were lower, and some highly adapted species have invaded from the IWP. The paper closes with a discussion of future directions in research.

Hydrostatic Pressure—Temperature effects on Deep-sea Colonisation

SynopsisA diverse benthic and bathypelagic fauna was first incontrovertably established by the deep-sea samples of H.M.S.Challenger, and demonstrated the ability of organisms to live and reproduce in the deep, dark and cold abyssal environment of enormous hydrostatic pressure as high as 1000 atm (14 000 psi) on trench floors at 10 000 metres. The investigations of Regnard (1891), Fontaine (1930) and Ebbecke (1935) established that various shallow animals have the capacity to withstand increased hydrostatic pressure. This paper deals with the response of whole organisms, mainly shallow-water metazoans, to hydrostatic pressure-temperature effects. The level of occurrence of pressure-induced increased activity (R1), onset of paralysis or tetany (T) and LD50are discussed for tropical and temperate marine species in relationship to temperature and hydrostatic pressure. The pressure sensitivity and resistance exhibited by different species are examined in relation to various hypotheses and theories such as (1) group effect, in which Schlieper (1968) claims that those shallow species that belong to the group which has successfully colonised the deep sea, such as Echinodermata, Mollusca, Isopoda, have a higher pressure resistance; (2) pressure resistance as a species or genetic property; (3) environmental impact, in which deeper species have a greater pressure resistance; and (4) finally a re-examination of temperature and pressure effects as these relate to deep-sea colonisation.