Grey mullets are funny fish. When fenced off - they''ll just jump over the net corkline and laugh at you from the outside. They may also jump back and forth - just for fun.
This is why fishermen, especially in the Mediterranean, China, and around the Indian Ocean, have been using ‘verandah’ nets for a long time. Well, grey mullets are not the only fish that jump to escape being fenced off. Carps and some other fish, such as tilapia, are also among the jumpers, and represent the main catch in verandah-styled gear in some Asian countries, but the mullet high-jumpers no doubt are in the top Olympic league in their size class.
Verandah
A verandah net (Italian ‘saltarello’), consists of a vertical net wall with a 1.5-2m wide strip of netting mounted all along its corkline, bordered by another corkline. To keep it horizontal and well spread in water, bamboo sticks or, nowadays, plugged plastic tubes, are fit at intervals into the verandah. In some areas the verandah is made of trammel netting, which keeps the fish entangled. Verandah nets come in two main forms: fixed set nets and floating. The set nets, usually fixed across known swimming path of the fish, may be hung on stakes, either in a straight line, or as a weir, in a semi-surrounding or spiral form, sometimes with ‘wings’ guiding the fish into the verandah-net trap. The floating ones are set around spotted fish schools. Often fishermen in auxiliary small boats enter the surrounded or semi-surrounded space and create noise to scare the fish into the net.
Grey mullets have served as an important source of food in Mediterranean Europe since Roman times. The family Mugilidae includes about 80 species in 17 genera, half of them in just two genera (Liza and Mugil). Mullets are distinguished by the presence of two separate dorsal fins, small triangular mouths, and the absence of a lateral line. They feed at the lowest trophic levels on plants, detritus and algae, and most mugilids have unusually muscular stomachs and a complex pharynx to help with digestion.
Mullets are grown in ponds and semi-enclosed water bodies in Egypt, China, Hawaii, Italy, Japan, Philippine, Taiwan, Russia, Israel, and other parts of the world. In most cases they're grown in polyculture with carps, tilapia, and milkfish. Mullets, especially the flathead grey mullet Mugil cephalus and thinlip mullet Liza ramada, while highly esteemed, and therefore, massively cultured in Egypt, represent worldwide the bulk of the farmed mugilids.
Flathead
Flathead grey mullet is a common species in the tropical and temperate waters of the Atlantic. They occur at temperatures ranging from 8-24 deg C, from the Bay of Biscay southward, in the whole of Mediterranean and Black Sea, as well as in the temperate Pacific, and in the Indian Ocean. Last century, they were introduced into the Caspian Sea, where they have abounded since. They are usually found in schools in calm waters close to shore, around mouths of rivers, streams and inlets, and in brackish or hyper-saline (waters saltier than seawater) bays, lagoons, and harbours, mainly over sand or mud. The flathead is an omnivorous feeder, feeding on zooplankton, small benthos including invertebrates, and algae. When food is available they also feed at the surface.
Flathead mullets are caught with beach seines, gillnets, cast nets, liftnets, barrier nets, trammel nets, and other artisanal gear. They reach a maximum size of 120cm, but are commonly caught at 35-50cm. Apart from some limited induced breeding, grey mullet culture depends on fingerlings collected from coastal waters. Among the countries with the largest catches are Egypt, Korea, Republic of China, and Venezuela.
Grey mullets fetch the best prices, where marketed fresh or fresh-frozen. In certain areas, for lack of onboard refrigeration or well-equipped beach-landing installations, and also for lack of demand for the costly fresh fish, they are processed into dried, salted product. Their roe, which in some areas, such as Egypt and the Far East, is relatively highly valued, is sold fresh, salted and dried, or smoked.
Egypt
Egypt has used wild-caught mullet seed for the annual restocking of inland lakes for at least 80 years. The world's mullet empire, it boasts over 90% of the world's grey mullet farming yield. The positive experience with collection of wild fingerlings at low costs has inhibited the development of hatcheries. With 156,400mt produced in 2005, mullets are very important in the national aquaculture production. Current legislation prohibits wild seed fisheries except under the direct supervision of the relevant authorities.
In 2005, 69.4 million mullet fry were caught for both aquaculture and culture-based fisheries. A parallel illegal fry fishery exists, however, affecting management and statistical data. The effect of wild seed fisheries on the wild stocks of mullet is not well studied. The negative effect of the fingerling collection activity is a matter of debate between fish farming and capture fisheries communities, although the capture of wild mullet fisheries has shown no observable effect of fry collection on mullet yields during the last 25 years.
Taiwan and Israel
Taiwanese scientists and fish farmers pioneered induced breeding and larval rearing of flathead grey mullet in the 1960s, with the first success in 1969. During the 1970s, the complete generation cycle was achieved, contributing to artificial breeding of grey mullet, as well as other marine finfish. However, artificial breeding of grey mullets has not been applied on a wide commercial basis, due to the great availability of fry at much less financial cost.
In Israel, where the artificial breeding of grey mullet has been achieved in parallel and in cooperation with the Taiwanese, the fingerlings for annual stocking in Lake Kinneret and fish ponds also come cheaper from the wild.
Still, the ability to induce spawning and the more difficult larval rearing in fast growing grey mullet species should counterweigh their overfishing, and enable the jolly mullets to keep jumping.
