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Tags: chondrichthyans, declines, extinction, FAO, fisheries, fishing, management, rays, sharks
Categories : coasts, fish, fisheries, marine, ocean
Please don’t eat me
How do you prevent declines of species you cannot even see? This is (and has always been) the dilemma for fisheries because, well, humans don’t live underwater. Even when we strap on a metal tank full of air and a pair of fins, we’re still more or less like wounded astronauts peering through a narrow window of glass at the huge, largely empty, ocean space. It’s little wonder then that we have a fairly crap system of estimating fish abundance, and an even worse track record of managing them sustainably.
But humans love to eat fish – the total world estimate of legal fisheries landings is something in the vicinity of 190 million tonnes in 2013, up from 18 million tonnes in 1950 (according to FAO). We’re probably familiar with some of the losers of that massive harvest, with species like tunas, bill fishes and orange roughy making the news for catastrophic declines in abundance over the last 30-40 years. And we’re not even talking about the estimated tragedy that is illegal, unreported and unregulated (IUU) fishing.
Back in 1999, the FAO started to report that sharks – the new-ish target of many world fisheries resulting from the commercial extinction of many other fin fish fisheries – we’re starting to take the hit. Once generally ignored by fishing industries, sharks soon became popular target species. Then in 2003, Julia Baum and colleagues famously (and somewhat controversially) sounded the alarm for sharks in the Gulf of Mexico by some claims of major and catastrophic declines of large, predatory sharks. While some of the subsequent to-ing and fro-ing in the literature challenged these claims, Baum’s excellent work was ultimately vindicated.
Since then, more and more evidence that sharks are in trouble has surfaced, including the assessment of the reported (again, only legal) catch indicated heavy depletion of coastal sharks even by 1975, and the estimate that 25% of all shark and ray species have an elevated extinction risk, mainly resulting from overfishing. Now even the direct fisheries landings statistics are confirming this grim tale. Read the rest of this entry »
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Tags: Apex predator, culling, environment, human-wildlife conflict, lethal, marine, policy, shark, top predator, WA, Western Australia
Categories : Australia, biodiversity, coasts, connectivity, conservation, decline, demography, environmental policy, extinction, fish, fisheries, harvest, impact, management, marine, minimum viable population, modelling, population dynamics
A major media release today coordinated by Jessica Meeuwig in Western Australia makes the (obvious) point that there’s no biological justification to cull sharks.
301 Australian and International Scientists experts have today provided their submission to the Western Australia Environmental Protection Authority (EPA), rejecting the scientific grounds for the proposed three-year drum-line programme.
Coordinating scientist, Professor Jessica Meeuwig from the University of Western Australia said:
“To have over 300 researchers, including some of the world’s top shark specialists and marine ecologists, all strongly agreeing that there is no scientific basis for the lethal drum-line programme, tells you how unjustified the government’s proposal is. If the EPA and the Federal Minister for the Environment are using science for decisions, the drum-line proposal should not be approved.”
The experts agree that the proposal presents no evidence that the lethal drum-line programme, as implemented, will improve ocean safety. It ignores evidence from other hook-based programs in Hawaii and Queensland that have been shown to be ineffective in reducing shark attacks on humans.
Dr. Christopher Neff from the University of Sydney stated:
“There is no evidence that drum lines reduce shark bites. The Western Australia EPA now faces a question of science versus politics with global implications because it is considering establishing a new international norm that would allow for the killing of protected white sharks.”
The drum lines are ineffective and indiscriminate, with 78% of the sharks captured not considered ‘threatening’ to humans. Yet, scientifically supported, non-lethal alternatives such as the South African ‘Shark Spotter’ and Brazil’s ‘Tag and Remove’ programmes are not adequately assessed as viable options for Western Australia. Read the rest of this entry »
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Tags: biodiversity, conservation, degradation, environment, loss, native vegetation clearing, South Australia, State of the Environment
Categories : alien species, Australia, biodiversity, carbon, carbon trading, climate change, coasts, conservation, deforestation, ecosystem, ecosystem function, ecosystem services, environmental policy, extinction, fragmentation, function, habitat loss, invasive species, kelp, logging, mammal, management, marine, marine protected area, monitoring, planning, prioritisation, protected area, recovery, reforestation, reserve, restoration, South Australia, The University of Adelaide, threatened species, water
South Australia State budget percentage expenditures for health, education and environment
Yesterday I gave the second keynote address at the South Australia Natural Resource Management (NRM) Science Conference at the University of Adelaide (see also a brief synopsis of Day 1 here). Unfortunately, I’m missing today’s talks because of an acute case of man cold, but at least I can stay at home and work while sipping cups of hot tea.
Many people came up afterwards and congratulated me for “being brave enough to tell the truth”, which both encouraged and distressed me – I am encouraged by the positive feedback, but distressed by the lack of action on the part of our natural resource management leaders.
The simple truth is that South Australia’s biodiversity and ecosystems are in shambles, yet few seem to appreciate this.
So for the benefit of those who couldn’t attend, I’ve uploaded the podcast of my slideshow for general viewing here. I’ve also highlighted some key points from the talk below: Read the rest of this entry »
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Tags: biodiversity, map, marine, marine protected area, marine reserves, reserve design, selection
Categories : Australia, coasts, conservation, conservation biology, exploitation, fish, fisheries, harvest, marine, marine protected area, MPA, protected area, reserve
The real measure of conservation progress, on land or in the sea, is how much biodiversity we save from threatening processes.
A new paper co-authored by Memorial University’s Dr Rodolphe Devillers and an international group of researchers argues that established global marine protected areas are too often a case of all show with no substance and do not adequately protect the most vulnerable areas of the world’s oceans.
“There is a big pressure internationally to expand global MPA coverage from around 3 % of the oceans to 10 %, resulting in a race from countries to protect large and often unused portions of their territorial waters for a minimal political cost,” said Mr. Devillers. “Marine protected areas are the cornerstone of marine conservation, but we are asking whether picking low-hanging fruit really makes a difference in the long-term, or if smaller areas currently under threat should be protected before, or at the same time as, those larger areas that are relatively inaccessible and therefore less used by people.
“We need to stop measuring conservation success in terms of square kilometres,” he added. “The real measure of conservation progress, on land or in the sea, is how much biodiversity we save from threatening processes. Metrics such as square kilometres or percentages of jurisdictions are notoriously unreliable in telling us about the true purpose of protected areas.” Read the rest of this entry »
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Tags: disturbance, noise, ocean, physiology, strandings
Categories : coasts, conservation, environmental policy, marine
|Killer whales are social animals that navigate all oceans and seas between the Arctic and Antarctica – they can be regarded eusocial since reproduction ceases around 40 years of age and menopausal females help care for offspring: like humans [13, 14]. Group cohesion in killer whales relies on a complex repertoire of vocalisations including clicks, whistles and calls. Sounds are instrumental for prey searching, orientation and communication. Foote  focused on calls, which are made up of series of discrete sounds that resemble squeaks, screams, and squawks to the human ear. It has been postulated that individuals learn to vocalise by imitation of peers of the same pod, and that only the base structure has a genetic, hence heritable, component . Regardless, pods develop regional dialects. Those dialects, along with aspects of diet, genetics, morphology and behaviour, differentiate the three main lineages of killer whales (resident, transient and open sea) that might have been genetically isolated for ~ 150 to 700 thousand years and, potentially represent different taxa [16, 17]. The species might abandon the IUCN conservation category of ‘Data Deficient’ as soon its taxonomic uncertainty is resolved.Resident killer whales form matrilineal groups of 2 to 15 individuals (the matriarch and her offspring) – known as pods, in turn subdivided into subpods centred around grandmothers and great-grandmothers. The Southern Resident population is regarded as an acoustic clan comprising 3 pods currently numbering 81 individuals = 26 (J pod) + 19 (K pod) + 36 (L pod) (2013 survey), among whom the matriarch Granny is the oldest at 103 years! This clan feeds mainly on fish, and dwells in the coastal waters between British Columbia (Canada) and Washington State (USA), particularly south of Vancouver Island – nothing is known about where they spend the winter. The clan lost 20 % of its members between 1995 & 2001, and 13 more by 2013, and now faces the decline of its main prey: Chinook salmon (Oncorhynchus tshawytscha) . The two pics show two sub pods of this clan swimming close to a whale-watching boat near Friday Harbour (San Juan Island) and a Chinese ship at Puget Sound (Seatle, USA). Photo credits: Marla Holt, NOAA/NMFS Northwest Fisheries Sciences Center.
Acoustic pollution has become a transnational issue, particularly in marine ecosystems  by virtue of the physical fact that sounds travel in water farther and faster than in air. In our noisy, modern world, many species are now forced to modify their vocal repertoire in response to noise. The pivotal social role that vocalisations play in all cetacean species makes these predators and filter feeders particularly vulnerable to this environmental problem.
Last night, an ambulance siren woke me, only seconds before the neighbour’s washing machine started spinning, and a good friend of mine rang from overseas. Gradually more and more people are living in societies plugged in to noisy mechanical and electronic devices 24 hours a day, 356 days a year.
Engine-powered vehicles are the main source of anthropogenic noise, and their numbers can grow even at a higher rate than the human population – so spreading not only diseases  but also decibels over a global network of travelling routes. In an ecological context, we refer to noise as a kind of sound (= energy wave detected by an auditory system) that is not considered a biologically meaningful cue by wildlife (including us) and might also cause physiological stress. Experts refer to ‘masking’ as those situations in which noise interferes the perception or emission of sounds that matter to the life history of species – a global concern in both terrestrial  and aquatic  ecosystems.
Andy Foote  has assessed the effect of vessel traffic on the vocal behaviour of the three pods forming the Southern Resident population of killer whales (Orcinus orca¸ see video). He recorded calls from these cetaceans from a ship, and through an array of submarine microphones in Haro Straight, between San Juan Island (Washington State, USA) and Vancouver Island (British Columbia, Canada). Between the 1990s and the 2000s, local traffic density had multiplied by a factor of 5 and currently, > 20 whale-watching vessels follow these killer whales daily among an active fleet of > 70 commercial vessels. Foote compared call length through 35 hours of underwater killer whale recordings over three periods (1977-1981, 1989-1992, 2001-2003), each comprising situations in which the pods were exposed to both noisy and quiet environments. Over the study, call length varied between 0.3 and 2.0 seconds; while on average, L-pod calls were the shortest (0.6-0.8 seconds), and J-pod calls the longest (0.9-1.0 seconds). Read the rest of this entry »
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Tags: Complex system, Ecosystem, macroalgae, predator, productivity, resilience, Seaweed, stability
Categories : algae, biodiversity, coasts, conservation, function, kelp, marine
© C. Hilton
Here at ConservationBytes.com, My contributors and I have highlighted the important regulating role of predators in myriad systems. We have written extensively on the mesopredator release concept applied to dingos, sharks and coyotes, but we haven’t really expanded on the broader role of predators in more complex systems.
This week comes an elegant experimental study (and how I love good experimental evidence of complex ecological processes and how they affect population persistence and ecosystem stability, resilience and productivity) demonstrating, once again, just how important predators are for healthy ecosystems. Long story short – if your predators are not doing well, chances are the rest of the ecosystem is performing poorly.
Today’s latest evidence comes from on an inshore marine system in Ireland involving crabs (Carcinus maenas), whelks (Nucella lapillus), gastropd grazers (Patella vulgata, Littorina littorea and Gibbula umbilicalis), mussels (Mytilus edulis) and macroalgae. Published in Journal of Animal Ecology, O’Connor and colleagues’ paper (Distinguishing between direct and indirect effects of predators in complex ecosystems) explains how their controlled experimental removals of different combinations of predators (crabs & whelks) and their herbivore prey (mussels & gastropods) affected primary producer (macroalgae) diversity and cover (see Figure below and caption from O’Connor et al.). Read the rest of this entry »