A couple of articles over the last few weeks do make interesting and/or disturbing reading: I think it is pretty much a given that for wild fisheries to have much chance of survival they must be managed. In this light recent gene marker studies on fish sales raise both hopes that we can now clearly identify the provenance of a fish on the fishmonger’s counter, and a warning that some existing certification schemes are not working as well as they need to. Farmed fish may be managed, but that also makes them subject to pretty unpleasant management practices, such as the practice of eye-stalk ablation, which apparently speeds maturity of black tiger shrimp…
We start, however, with one of the big stories in the popular press over the last few weeks, the latest estimate of the total number of species on the planet. To be pedantic we should perhaps say eukaryotic species, though the term ‘species’ is not very easy to apply to prokaryotes…
Let me count the ways: 8.7 million (±1.3 million) eukaryotic species globally, of which approx. 2.2 million (±0.18 million) are marine – 91% of species in the ocean still await description…
Mora C, Tittensor DP, Adl S, Simpson AGB, Worm B (2011) How Many Species Are There on Earth and in the Ocean? PLoS Biol 9(8): e1001127. doi:10.1371/journal.pbio.1001127
Photos reveal benthic habitat dynamics: A unique series of underwater photographs taken over a period to 25 years has allowed scientists to look at how communities of sponges and anthozoans change over time. These species are surprisingly long-lived with just over 3% of the combined population dying each year, a rate approximately balanced by influx of new individuals. The low turn-over suggests that these communities are very susceptible to human disturbance.
Teixidó N, Garrabou J, Harmelin J-G (2011) Low Dynamics, High Longevity and Persistence of Sessile Structural Species Dwelling on Mediterranean Coralligenous Outcrops. PLoS ONE 6(8): e23744. doi:10.1371/journal.pone.0023744
As wide as it is tall? Vertical variations in communities on rocky shores are well known, and are driven by stresses due to predator access and exposure. Longitudinal differences in community structure along a rocky shore are also common, but less well understood. Possibilities include propagule retention on the shoreline, foundation species effects, and physical influences.
Valdivia N, Scrosati RA, Molis M, Knox AS (2011) Variation in Community Structure across Vertical Intertidal Stress Gradients: How Does It Compare with Horizontal Variation at Different Scales? PLoS ONE 6(8): e24062. doi:10.1371/journal.pone.0024062
Fish mussel in: The presence of sub-tidal reefs greatly increases predation on mussels. The reefs act as a low-water refuge for predatory fish, which forage over the mussel bed at high water.
Rilov G, Schiel DR (2011) Community Regulation: The Relative Importance of Recruitment and Predation Intensity of an Intertidal Community Dominant in a Seascape Context. PLoS ONE 6(8): e23958. doi:10.1371/journal.pone.0023958
Rumbling shrimp: Male shrimps make rumbling noises in turbid waters, almost certainly to communicate territory and attract mates. The behaviour is specific to wild habitats, perhaps because visibility is poor, or distances between shrimps are greater, so visual communication systems don’t work. ScienceDaily (Sep. 9, 2011)
Green tunicates: Studies indicate that the photosymbiont blue-green algae living within tunicates in the Bahamas are usually structured by the ascidian host, but can also be dominated by location effects.
López-Legentil S, Song B, Bosch M, Pawlik JR, Turon X (2011) Cyanobacterial Diversity and a New Acaryochloris-Like Symbiont from Bahamian Sea-Squirts. PLoS ONE 6(8): e23938. doi:10.1371/journal.pone.0023938
Heal yourself: Corals have the same basic pattern of wound healing as mammals.
Palmer CV, Traylor-Knowles NG, Willis BL, Bythell JC (2011) Corals Use Similar Immune Cells and Wound-Healing Processes as Those of Higher Organisms. PLoS ONE 6(8): e23992. doi:10.1371/journal.pone.0023992
Global bug-map: The first attempt to bring together information about bacterial communities in the marine ecosystem shows it to be diverse!
Zinger L, Amaral-Zettler LA, Fuhrman JA, Horner-Devine MC, Huse SM, et al. (2011) Global Patterns of Bacterial Beta-Diversity in Seafloor and Seawater Ecosystems. PLoS ONE 6(9): e24570. doi:10.1371/journal.pone.0024570
To CO2 you will return: The Alphaproteobacteria are the most abundant heterotrphs in the ocean. They are equipped with a tiny genome that specialises in converting single carbon compounds – such as methanol and formic acid – into carbon dioxide, and are a vital mechanism for the return of dissolved organic carbon from the ocean to the atmosphere as CO2.
Sun J, Steindler L, Thrash JC, Halsey KH, Smith DP, et al. (2011) One Carbon Metabolism in SAR11 Pelagic Marine Bacteria. PLoS ONE 6(8): e23973. doi:10.1371/journal.pone.0023973
Tough reef: Reefs around the Indo-Pacific island of Moorea have recovered after several major disturbances. In each instance, after the reef has damaged the numbers of herbivorous fish has increased rapidly, ensuring that macro-algae do not get chance to dominate the ecosystem. The herbivore population is recruited from the lagoon emphasising the importance of the link between the two in forming a stable reef ecosystem.
Adam TC, Schmitt RJ, Holbrook SJ, Brooks AJ, Edmunds PJ, et al. (2011) Herbivory, Connectivity, and Ecosystem Resilience: Response of a Coral Reef to a Large-Scale Perturbation. PLoS ONE 6(8): e23717. doi:10.1371/journal.pone.0023717
Comb stopped by fresh water: Studies in the Baltic suggest that the invasive comb jelly Mnemiopsis leidyi is unable to form a sustainable population at salinities less than 15ppt.
Jaspers C, Møller LF, Kiørboe T (2011) Salinity Gradient of the Baltic Sea Limits the Reproduction and Population Expansion of the Newly Invaded Comb Jelly Mnemiopsis leidyi. PLoS ONE 6(8): e24065. doi:10.1371/journal.pone.0024065
1000 years whale watching: Review of Portuguese historical sources on cetacean sitings.
Brito C, Sousa A (2011) The Environmental History of Cetaceans in Portugal: Ten Centuries of Whale and Dolphin Records. PLoS ONE 6(9): e23951. doi:10.1371/journal.pone.0023951
4%: The area of the world’s oceans that would need to be converted into reserves to protect ‘the vast majority’ of marine mammals. ScienceDaily (Aug. 30, 2011)
Fisheries and exploitation
These are not the fish we are looking for: Genetic markers indicate that sales of Chilean Sea Bass are often not Chilean Sea Bass, and much of the catch was not from certified sustainable fishing grounds. About 15% of the fish analysed was bogus, raising questions about tracability in the certification scheme. ScienceDaily (Aug. 22, 2011)
Deep sea fish in trouble: Report indicates that almost none of the current deep-sea fisheries are sustainable. ScienceDaily (Sep. 9, 2011)
Fine-grained management may increase sustainable yields: Managing fish stocks geographically at the individual species level could increase sustainable catches by 25%.
Hamilton SL, Wilson JR, Ben-Horin T, Caselle JE (2011) Utilizing Spatial Demographic and Life History Variation to Optimize Sustainable Yield of a Temperate Sex-Changing Fish. PLoS ONE 6(9): e24580. doi:10.1371/journal.pone.0024580
SELTRA-trawl: reduces by-catch of cod in langustine fisheries. ScienceDaily (Aug. 29, 2011)
Hake today, hake tomorrow: Despite fisheries pressure northern European hake stocks have stood up pretty well, this appears to be due to warmer waters encouraging the survival of juvenile stages. ScienceDaily (Aug. 24, 2011)
Salmon in trouble: A new study indicates that the decline in wild salmon stocks are due to a number of factors acting in concert.
Otero J, Jensen AJ, L’Abée-Lund JH, Stenseth NC, Storvik GO, et al. (2011) Quantifying the Ocean, Freshwater and Human Effects on Year-to-Year Variability of One-Sea-Winter Atlantic Salmon Angled in Multiple Norwegian Rivers. PLoS ONE 6(8): e24005. doi:10.1371/journal.pone.0024005
Farming offshore: Blue fin tuna farmed off-shore suffer less from parasites.
Kirchhoff NT, Rough KM, Nowak BF (2011) Moving Cages Further Offshore: Effects on Southern Bluefin Tuna, T. maccoyii, Parasites, Health and Performance. PLoS ONE 6(8): e23705. doi:10.1371/journal.pone.0023705
Gouge out their eyes: Apparently tiger shrimp mature faster if their eyes are ‘ablated’. This study is looking for alternatives, but it sheds light on a rather disturbing and unpleasant practice…
Uawisetwathana U, Leelatanawit R, Klanchui A, Prommoon J, Klinbunga S, et al. (2011) Insights into Eyestalk Ablation Mechanism to Induce Ovarian Maturation in the Black Tiger Shrimp. PLoS ONE 6(9): e24427. doi:10.1371/journal.pone.0024427
Kelp farm? Further studies indicate that large-scale kelp farming may provide useful amounts of fuel. ScienceDaily (Aug. 30, 2011)
Fast fuel: Yeast allows sugars in seaweed to be quickly converted into biofuels: ScienceDaily (Aug. 30, 2011)
A clam’s take on climate change: Clams can live for 100 years, and they lay down a record of the environment they are growing in in their shells. Just like tree-rings, they can be used to plot past climates. Results indicate that climate variations seen in the tropical Pacific have been strongly connected with those in the Antarctic for the last 50 million years. The good news from this is that the Pacific oscillations (El Niño) have persisted through past warm periods, so will probably continue through the current warming phase. ScienceDaily (Aug. 20, 2011)
Unstable sea-levels: Bahamian corals indicate tha sea-levels have varied considerably over the last warm inter-glacial:. ScienceDaily (Sep. 11, 2011)
King crabs on the march: Another report about king crabs finding their way into Antarctic waters, which have warmed up enough for them to thrive. ScienceDaily (Sep. 8, 2011)
Shipwrecks as climatic time capsules: The biological communities on WW2 shipwreck sites off the North American coast have been recorded to provide a baseline for monitoring climatic changes. ScienceDaily (Aug. 26, 2011)