Dolphins in a bottle

Giovanni Bearzi and other four researchers from the Tethys Research Institute recently published a paper reporting the work done in the Gulf of Amvrakikos during 2002-2005, resulting in the individual identification of 148 bottlenose dolphins.

This work shows that dolphin density and levels of site fidelity are high, and this was related primarily to prey availability, particularly of epipelagic schooling fish.

The importance of this semi-closed basin for bottlenose dolphins and other threatened species such as marine turtles and endangered birds supports the adoption of measures aimed to conserve its valuable ecosystems and raise the naturalistic profile of the area, while promoting environment-conscious development.

Paraphrasing the famous song by The Police, Dolphins in a Bottle sends a S.O.S. to the world to protect these unique animals and their environment, and we hope that someone gets it :-)

Silvia Bonizzoni

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Bearzi G, Agazzi S., Bonizzoni S., Costa M., Azzellino A. 2008. Dolphins in a bottle: abundance, residency patterns and conservation of bottlenose dolphins Tursiops truncatus in the semi-closed eutrophic Amvrakikos Gulf, Greece. Aquatic Conservation: Marine and Freshwater Ecosystems 18(2):130-146. (502 Kb)

Rocky deserts at sea: causes and solutions

Many vegetated systems in temperate regions throughout the world may face dramatic ecosystems shifts to unvegetated states. So, flourishing kelp forests may become desolated bare rocky substrates void of the rich floras and faunas usually associated to forests.

In the Mediterranean there are no kelp forests, but rocky bottoms can be covered by macroalgae (e.g. Cystoseira spp) that host juvenile and adult stages of many invertebrate and fish species. The persistence of these macroalgal beds, that greatly contribute to maintain coastal biodiversity and productivity, is the result of a delicate equilibrium among environmental conditions, interactions among species and human disturbance.

In recent years it has been demonstrated that in Mediterranean rocky reefs where fishing is particularly intense fish predators may decrease in abundance and size. Their decreased predation impact on preys, including sea urchins (the most important grazers in such systems), may reflect in a dramatic increase of prey abundance.

The ultimate consequence of the fishing impact may thus be an increased grazing impact of sea urchins that causes the transition from macroalgal beds to the so-called ‘barrens’, that is bare rocks partially covered by encrusting coralline algae. They are a sort of rocky deserts.

How to cope with this? Management of complex natural systems is not easy because many processes may interact. Formation of barrens, for instance, can be also a consequence of other processes like water warming or sedimentation. However, fishing restrictions and fish predator recovery may be useful to reverse this phenomenon.

From this perspective, there is increasing evidence that the creation of effective Marine Protected Areas (and not paper parks) can allow fish predators to recover along with their potential in controlling sea urchin populations and their effects on macroalgae.

At the MPA of Torre Guaceto (SE Italy), in the same rocky reefs where in the past (before the establishment of the MPA) there were barrens, there are at present (after about 7-8 years of effective protection) more fish predators, less sea urchins and lower barren covers than outside the MPA, which is the proof that properly managed MPAs can allow the entire ecosystems to recover.

Paolo Guidetti

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For more information:
Guidetti P. 2006. Marine reserves reestablish lost predatory interactions and cause community changes in rocky reefs. Ecological Applications 16(3):963–976.

How climate influences the deep sea

Picture the Grand Canyon in Arizona - then place it under the sea: the Mediterranean seafloor is criss-crossed with deep submarine canyons that in sheer size put their land counterpart to shame. Rivers of dense waters flow through these canyons, their capacity varying depending on climate-induced phonomena.

During such an event, the amount of water transported in 4 months from the Gulf of Lion to the deep Western Mediterranean via the Cap de Creus canyon equalled 2 years of input from all rivers draining in the Mediterranean.

How these dense shelf water cascading in the Gulf de Lion affect the population of the deep sea shrimp Aristeus antennatus, the most valuable deep-sea living resource in the Mediterranean Sea, was recently discovered by Spanish researchers. Initially, the strong currents (up to 80 cm/sec) displace shrimp populations from the normal fishing grounds, producing a temporary fishing collapse. However, the food provided by the currents soon leads to a large increase in recruitment - which results in plentiful landings of large shrimps 3-5 years after major cascading events.

These new findings resolve the paradox of a long-overexploited fishery that has not collapsed after 70 years of intense deep-sea trawling. But climate change is expected to cause a decrease of winter deep water formation in the Gulf de Lion, which in turn could decrease the frequency and intensity of dense shelf water cascading events. Without this regenerative mechanism, fishery pressure could quickly deplete the stock of Aristeus antennatus and other valuable deep-sea living resources in the area.

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For more information:
Company et al (2008) Climate influence on deep sea populations. PLoS ONE 3(1): e1431.
Eureka alert press release (Jan 15th 2008)

Global MPA database

MPA Global Database is a project that aims to create a database on the existing Marine Protected Areas, worldwide.

Based largely on information in the World Database on Protected Areas (WDPA), the project has two main goals: to develop a more robust global MPA baseline than currently exists, and to develop alternative scenarios of global MPA networks using spatial modelling techniques.

MPA Global Database contains a great variety of information such as: names of MPAs for each country, area covered and year of designation, mean area of MPAs, percentage of MPAs located in a specific latitude etc.

This database shows that 4435 MPAs exist worldwide and they cover an area of 2.35 million km2. These numbers sound misleadinly big, but the fact is: only 0.65% of the world oceans is covered by MPAs!

Even more impressive is the estimate of global no-take areas (areas where fishing is banned). The percentage of world oceans subject to this specific regulation is only 0.08% !

This database is a new tool for the marine conservation and shows how much still needs to be done to protect marine biodiversity.

Silvia Bonizzoni

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For more information:
http://mpaglobal.org
http://depts.washington.edu

Bycaught dolphins washing up dead on British coasts

A scaring number of dolphins and porpoises are washing up dead on British coasts.

Since the beginning of the year, 29 animals have been found on the beaches of south-west England. Experts suspect that most have drowned after being caught up in fishing nets.

Some dolphins have their tails or beaks amputated probably due to a useless attempt to free them from the nets, in other individuals bellies have been sliced open after death to try to make them sink.

Mark Simmonds, science director at the Whale and Dolphin Conservation Society, said: "It is a horrid way for these dolphins to die and you can see that when they come ashore. Fishermen are getting more adept at hiding the evidence and what we see on land is only a proportion of the problem."

On the other hand, Andy Wheeler, from the Cornish Fish Producers' Organisation, said: "Every reasonable effort is made by fishermen to avoid bycatch of dolphins. The jury is still out on whether the level of bycatch is a threat to the population."

Considering that the fishing effort is increasing worldwide, it’s time to increase also our effort to eliminate bycaught animals, whether cetaceans, birds, marine turtles, sharks or others.

Silvia Bonizzoni

Photo: WDCS

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For more information:
http://www.telegraph.co.uk/earth
http://www.wdcs.org/news

French driftnets killed by the European Court of Justice

Oceana, an international organization that works to protect and recover the oceans in the world, has announced that the European Court of Justice has refused to grant France exemption from the prohibition of the use of driftnets in the Mediterranean.

Driftnets used to catch bluefin tuna and swordfish were outlawed in the European Union from 2002 because they constitute a threat to the conservation of cetaceans, sea turtles and sharks. However, years after the ban entered into force, France and Italy have continued using driftnets. While operations in Italy have been downright illegal, the French fleet had taken advantage of legal loopholes to continue carrying out its activities, with full support from its government. French driftnets have caused significant mortality to striped dolphins in the waters of the Pelagos Sanctuary for Mediterranean cetaceans.

The European Court of Justice ruled that the French driftnet fleet should not have a temporary exemption from the ban as requested by its government. As such, France cannot offer the driftnet fleet its protection in 2008. Any fishing vessel using this gear to catch bluefin tuna must be sanctioned by French authorities.

Giuseppe Notarbartolo di Sciara

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For more information:
Oceana's press release, 17 March 2008

Mediterranean forecast

A great information tool for scientists working in our inland sea is the Mediterranean Ocean Forecasting System (MFS) created by GNOO, the Italian National Applied Oceanography Group.

Daily temperature, salinity, height, anomalies at the surface or in the depths; a forecast for the next 10 days and an analysis of the past 7 days are available.

Other regional forecasting systems, amongst others:

• the Adriatic Sea
• the Sicilian Channel
• the North-West Mediterranean

(image: MFS)

Crazy race for the last Mediterranean tuna

A new WWF report, 126 pages long, provides the first real estimate of the actual catch capability of the Mediterranean purse seine fleet targeting bluefin tuna.

The results are discouraging: few tuna stocks left are driven by unregulated and unsustainable fisheries to a tragic end point.

Without considering the potential catch from other fleets, such as pelagic trawlers, longliners etc., the Mediterranean purse seine fleet has a calculated yearly catch potential of 54,783 metric tonnes. This amount is twice the fishing capacity of current quotas and more than 3.5 times the catch levels recommended by scientists to avoid stock collapse.

How could we ever get to this point? Systematic upward adjustment of quotas, under-reporting of catches, uncontrolled increase in fishing capacity, illegal fishing, ever-increasing market demand ever-expanding fleet size and efficiency... these are some ingredients of the foolish management that brought the tuna stocks to nearly collapse.

Sergi Tudela, Head of Fisheries at WWF Mediterranean, has a clear view of the situation: “The fishery is unsustainable in every way – economically, socially, and ecologically. The time to act is now – while there are still bluefin tuna to save in the Mediterranean”.

Silvia Bonizzoni

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For more information
http://www.panda.org
To download the report
http://assets.panda.org

Ocean deserts

The world oceans are deeply affected by human activities, from pollution to resource overexploitation, but now there is a new problem.

The least biologically productive areas of the oceans are expanding much faster than predicted. This is the result of a new study conducted by researchers at the National Oceanic and Atmospheric Administration (NOAA) and the University of Hawaii.

The evidence of this expansion comes from data collected by a visual satellite sensor that reads reflective colour to measure the density of chlorophyll in phytoplankton, the microscopic organisms that are the base of the marine food web. Atlantic and Pacific Oceans are characterized by huge 'black' spots, which indicate zones of very low productivity. These zones, likened to deserts, now cover an estimated 51 million square kilometres in the two oceans and are replacing very fast adjacent prolific areas.

This change in ocean biology, probably linked to the warming of sea surface waters, can have deep consequences to all marine ecosystems. It may negatively affect all the marine food web from plankton to fishes, turtle and cetaceans.

Silvia Bonizzoni

(The image by NOAA shows black areas considered the least biologically productive)

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For more information:
www.noaanews.noaa.gov

"Protected" marine protected areas are better than "just" marine protected areas

An obvious statement? Not so, as it seems. Many Mediterranean coastal states have established marine protected areas (MPAs), however more than 50% of these have no management plans and their regulations, particularly as far as fisheries are concerned, are not enforced. As a result, fish assemblages in these "paper parks" often cannot be distinguished from those found in non-protected waters.

Paolo Guidetti (University of Lecce, Italy) and colleagues have recently published (Biological Conservation, doi:10.1016/j.biocon.2007.12.013) results from research on fish assemblages simultaneously conducted across 15 Italian rocky shore MPAs within the framework of the "Sistema Afrodite" programme.

The authors discovered that only three of the marine reserves investigated had adequate enforcement, and that the degree of recovery of target fish species was tightly linked to the level of surveillance conducted in the MPAs. The study demonstrates the importance of including compliance among the factors considered in evaluating the conservation effectiveness of marine reserves, and warns that in careless analyses positive ecological responses in properly managed reserves can be masked by neutral or even negative results in paper parks.

Giuseppe Notarbartolo di Sciara
(photograph by Tundi Agardy)

Guidetti P., Milazzo M., Bussotti S., Molinari A., Murenu M., Pais A., Spanò N., Balzano R., Agardy T., Boero F., Carrada G., Cattaneo-Vietti R., Cau A., Chemello R., Greco S., Manganaro A., Notarbartolo di Sciara G., Russo G.F., Tunesi L. 2008. Italian marine protected area effectiveness: does enforcement matter? Biological Conservation 141:699-709.

Rare monk seal sighted in Sardinia?

The sighting of a monk seal in the waters of the National Park of the Maddalena Archipelago (Sardinia, Italy), made two days ago, was reported in today's issue of La Nuova Sardegna, a local newspaper.

The seal, a young specimen only about 1.5 m long, was reportedly seen cavorting underwater around two skin divers without any trace of fear. One of them, Fannino Curreli - an experienced local diver - expressed no doubts about the identification of the species.

Monk seals, frequent in Sardinia until about 50 years ago, today have almost completely disappeared from the entire western Mediterranean, and sightings in Sardinia are now an extremely rare occurrence. If confirmed, the appearance of a monk seal off La Maddalena is encouraging because it indicates that these rare mammals could one day make a comeback if undisturbed.

Mediterranean monk seals were exterminated by direct killings, excessive fishing and pervasive human disturbance, and have now become one of the most endangered of the planet's mammals. It is thought that only 350-400 specimens of the species still exist in the entire Mediterranean Sea, mostly in Greek and Turkish waters.

Giuseppe Notarbartolo di Sciara

Mediterranean shark fisheries

Few elasmobranchs are subject to directed fisheries in the Mediterranean, but the region has the highest percentage of threatened sharks and rays in the world (42%).
Bycatch is the main cause of decline. Catsharks, dogfish and skates have a greater commercial value; other species may be discarded. In Italy elasmobranchs represent less than the 2% of reported total catches.

Bottom trawl fisheries catch various elasmobranchs such as catsharks and skates. Trammel nets may also catch larger species, including even basking and white sharks. Many shark species are taken as bycatch of Mediterranean deep-water fisheries. Migratory oceanic sharks constitute a large component of the bycatch in tuna and swordfish fisheries using longlines, driftnets and purse seines. Large driftnet fisheries are prohibited by the EU but the gear is still used by both EU and non EU boats.

Finning is not known to be practiced in the Mediterranean basin, but recently the Italian Coast Guard stopped a Spanish fishing boat finning in international waters just off the Calabrian coast (13 nautical miles out of Italy).

Eleonora de Sabata

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For more information:
Hareide et al. 2007. European Shark Fisheries: a preliminary investigation into fisheries, conversion factors, trade products, markets and management measures European Elasmobranch Association

Individual recognition of dolphins reported by Pliny the Elder 1931 years ago

Cetacean research pioneers David and Melba Caldwell wrote in their 1972 book “The world of the bottlenosed dolphin” that the earliest example of the practice of prolonged observation of cetaceans based on the recognition of individuals over extended time was that of Pelorus Jack - a Risso’s dolphin observed between 1888 and 1912 swimming near ships crossing Cook Strait, between the northern and southern portions of New Zealand.

Recently my attention was pointed to a writing by Pliny the Elder which moves back the clock of such scientific method by 1,811 years!

In the 9th book of his Naturalis Historia, published in 77 A.D., the ancient naturalist wrote about dolphins: “They grow fast, and it is believed that they reach their maximum size at 10 years of age. They can reach the age of 30, as discovered through the experimental cutting of nicks on their tails” (Adolescunt celeriter, X annis putantur ad summam magnitudinem pervenire. Vivunt et tricenis, quod cognitum praecisa cauda in experimentum).

Giuseppe Notarbartolo di Sciara

Using satellite images to protect the Ocean

Not everyone knows that satellite images can be used to support marine conservation.

The concept is simple. Satellites have global reach and can repeatedly capture images of any area, they can reveal the land/seascape disruption and habitat degradation caused by anthropogenic activities. They can be used to monitor industrial sites, logging operations, environmentally sensitive areas, urban sprawl, shipping traffic, fisheries, and resource-management practices, no matter where in the world they occur.

Also, they can be used to monitor fishing activities. Daniel Pauly, a world-renowned fisheries scientist, is the pioneer of this innovative idea. Pauly was inspired by a satellite image of a fleet of trawlers at work in the ocean. Looking at the image, he realized that trawlers could be seen so clearly that it would in theory be possible to monitor fishing from satellites and assess their impact. With historical and global archives, it is also possible to compare images to show changes over time. This kind of data could lead to restrictions on industrial fishing methods.

In addition to being a source of scientific data to document environmental change, satellite images may also represent a powerful communication tool. Using satellite photographs, we can document and communicate the impact of anthropogenic activities and promote a sustainable use of resources.

Silvia Bonizzoni

(The satellite photo shows mud trails made by shrimp trawlers off the mouth of the Yangtze River www.digitalglobe.com)
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For more information:
www.theglobeandmail.com
www.eurekalert.org
www.iht.com