Marine Fisheries News - Why Sharks are Special

Sharks are the top predators in our marine ecosystems. They are highly vulnerable to overfishing because they are long lived, slow to mature and produce fewer offspring compared with other fish. Sharks play an important role in our oceans by cleaning up dead and dying marine species.
How Many Sharks are Caught?

Silver Trevally – From the Shore

The silver trevally or Pseudocaranx dentex has to be my most favourite and cherished light tackle species in Tasmania. They are just an awesome little fish to catch, especially if you manage to hook one over that magical fifty centimetre mark! Personally, I began targeting the species many years ago on a variety of baits and artificial lures from a small stretch of beach in Georges Bay. At the time, they were the ultimate sports fish, the very thought of hooking up to one of these fish was enough to keep me saving up for more packets of soft plastics. One of the aspects I really enjoy about targeting trevally is their simplicity to catch. Sure, they aren’t as hard to catch as a big black bream, but at the end of the day, I think everyone would be happy with a large, hard fighting silver trevally. Over the years, I have discovered many trevally holding locations scattered along our coastlines, even up around Burnie! With their awesome fighting abilities and overall beauty, I can understand why the silver trevally is one of the most popular species Tasmania has to offer.

Saltwater shore bashing

The Christmas season is now upon us, many anglers will begin to pursue popular inshore species such as East Australian Salmon, Silver Trevally, Black Bream and Sand Flathead. Fishing from the shore has been one of my favourite methods of targeting specific species of fish for some time now and the very thought of discovering a new location is enough for me leave the boat at home. With Georges Bay and some North West hot spots being my favourite places to fish, many other destinations have either been discovered or successfully fished. Typical locations such as Red Rock on the North West coast has been producing many different species for a while now with the captures of good sized Silver Trevally, Gummy Sharks, Elephant Fish and Southern Garfish becoming more common. Some people worry and stress about not being able to access a kayak or boat in order to venture out onto the water but in reality, most anglers will have at least two great fishing spots that they can easily access from the shore.
When I began fishing from Red Rock on the North West coast with my good mate Jeremy Shaw, the possibility of encountering a Draughtboard Shark or Eagle Ray was enough to keep us coming back each weekend. Many days were spent fishing at Red Rock with colossal amounts of burley and junk food. Back then, captures of small East Australian Salmon and Sand Flathead were cherished and we never thought of leaving the rock for any reason other than the occasional trip out in the boat for a Mako Shark. During at least five years of fishing from Red Rock, we caught numerous and memorable fish including that of a rather large Seven Gilled Shark. It wasn’t until I began to seriously fish around the plentiful beaches and jetties of Georges Bay that I realized that fishing was the thing for me. Like the many hobbies that people enjoy, I got better at the sport and eventually became unstoppable. I believe that every angler needs to start off somewhere, land based fishing is a great way to begin the life long journey.

King George Whiting

There are a number of Whiting species found throughout Australia, and many Tasmanians would be surprised to learn that recreational fishing surveys report around 10,000 Whiting are caught in Tasmanian waters every year. These would mostly be sand whiting though. 
The King George Whiting is the prize. It is the largest and most well renowned species and is considered one of the best table fish around. 
Normally South Australia is spruiked as the KGW capital of Australia but in recent years Tasmanian waters have started to produce some regular numbers of good quality, well sized KGW. 

Bream on Fly

Tasmanian Bream are a fantastic sports fish that offer the Tasmanian angler a challenging and rewarding day on the water. Black Bream, in Tasmanian waters, have been able to grow to impressive sizes due to the limited angling pressure they receive and the healthy estuary systems they live in. Bream up to 2.5 kg are not uncommon in our waters and these very old fish are often seen and caught amongst schools of bream in the upper tidal reaches of a river during the spawning season. 

Meet the Flatheads

How many Flathead are caught in Tassie? Flathead are the most commonly caught recreational species in Tasmania, accounting for almost two-thirds of all fish caught. Over 1.8 million flathead were caught by Tasmanian recreational fishers between December 2007 and November 2008. 1.07 million of these flathead were kept and 745 000 (around 40%) were released, showing an increasing trend toward fishers doing the right thing by releasing undersize fish.
Interesting Flattie Facts

More on whitebait - From 1961

An extract from the Inland Fisheries Commission Annual Report 1961. Introduction In 1941, commercial exploitation began of the whitebait, Loverria sealii (Johnston).earlier the whitebait had been valued by anglers, who considered that the entry of great quantities of these small fish into the estuaries of rivers on the North- West and Northern Coasts, particularly from August to October, both provided a bountiful source of food for trout (Salmo trutta) and induced the trout to come into areas where they became more available to anglers. Dr M Blackburn of the CSRIO Division of Fisheries, in reports supplied to the Fisheries Division of the Department of Agriculture in 1948 and again in 1949, described the biology was followed by a sharp and substantial decline. A report of Dr Blackburn’s investigations was published in 1950 (Aust. J Mar. Freshw. Res. 1:155-98). Representations by the North-Western Fisheries Association and the former Salmon and Freshwater Fisheries Commissioners south the prohibition of further commercial exploitation of whitebait in the north and were referred to the writer by the Hon. Minister of Agriculture and Fisheries.

The Fish
The published reports show that the whitebait enter from the sea in spring for the purpose of spawning near the upstream limits of tidal waters, the fish are one year old and about two inches long. From 100 to 200 eggs are laid and adhere to submerged logs, stones, &c. Few adults survive for long after spawning. Eggs hatch in about three weeks and the young drift out to sea. Dr Blackburn fund that the whitebait of the Northern rivers belonged to a common stock which should be treated as one for purposes of management. Similarly there was another common stock in the Southern rivers. The Northern fish, when taken, are of higher quality because they comprise mainly gravid and unpigmented fish. The Southern fish, as taken, comprise of a higher proportion of darker, spent fish.

Fishing Methods
Tidal reaches of the two main Southern rivers, the Huon and the Derwent, are so broad and deep that effective netting with permitted apparatus is difficult, expect above the areas where the main spawning presumably takes place. Most of the Northern whitebaiting rivers have steep gradients to near the coast and have very short tidal reaches. Fishing is permitted by licensees only and is at present restricted to the months of August to December. A licensee may use up to four scoop nets, being not more than 30 inches in diameter at the mouth, nor more than five feet in depth. Such scoops may be fished as dip nets in the margins or as set nets with mouths facing downstream in the assumed path of fish in deeper water. At the peak of fishing activity which occurred in 1947, over 900 scoops were in use on Northern Rivers. Many such rivers are small and leads followed by fish could be almost completely blocked by scoops. If the fish tend to “see-saw” with the tide, or to drop back and return again as rain affects stream levels, the same fish might hae to pass and repass successive batteries of nets. The impracticability of marking such small fish makes it impossible to determine the precise movements of fish after entry and the extent of the escapement during the season. The catches for successive months in 1960 showed that over a third of the total was taken in August, approaching half in September and that thereafter quantities fell rapidly and were only about 3% after October.

Value of the Fishery
At the peak of production in 1947, when the yield of Northern rivers was about 30 times as great as in recent years, the wholesale value of each catch was only £16,000. Canneries took much of the catch. The Tasmanian whitebait has never achieved the special fish delicacy value of the New Zealand whitebait, which fetches several times the price. (The New Zealand Commercial whitebait comprises mainly larval Galaxias attenuatus, a species which, although present in Tasmania, is not sufficiently abundant here to support a fishery). The recent retail price of Tasmanian whitebait has been about 2s. 6d. a pound. Whitebaiting is not a traditional fishery of the kind that has lead to the construction of jetties and other capital assets. A licensee can equip himself for a very small sum, although in paces a rowboat is also desirable. It is not like an ordinary fishery, where the necessity for a substantial capital outlay can condition the rate of expansion. With the whitebait fishery, any appreciable improvement in runs of fish could be followed within a week by a sharp increase in the number of persons equipped with licences and scoops. At its peak, whitebaiting provided direct part or full time seasonal employment for about 230 persons – a number which has declined to about 65. Except for a very few professional fisherman, who would apply themselves to whitebait or other species, according to abundance and ruling prices, the fishing is carried out largely as a spare-time occupation by amateurs having other means of livelihood, or by pensioners. At its former peak, the fiery is said to have had a disturbing effect on regular employment. It has never been dependable and sole source of livelihood. The average earnings of whitebaiters, even at the 1947 peak, were only about £70, earned over a season of several months. In 1960, wen the total catch was a little better than in any of the previous five years, individual fisherman still took on an average only a sixth the quantity they took in 1947.
Destruction of the Whitebait Fishery
Although commercial whitebaiting had commenced a little earlier in the South, there was only slight activity in the North before 1943. Then the number of licenses increased about four-fold from 1944 to 1947. The peak in total production in 1947, a year which there was a 38% increase over the 1946 catch, yet a drop in yield per scoop, or fishing unit of about 27%. Data published by Dr Blackburn for the 1943-1948 seasons have been amplified by further records made available by the Secretary of the Fisheries Division of the Department of Agriculture. The number of rivers fished rose from three in 1943 to seven in 1945 and a maximum of eleven in 1947. The Mersey and the Leven each contributed to about one third of the total catch. The 1960 the number of rivers fished had fallen to eight and in the Inglis, Cam and Blythe the catch was less than 150 lb. each. The Leven and Mersey produced over three-quarters of the total, the balance coming from the Duck, Black and Rubicon. The drop in catch per scoop from 1550 lb. in 1946 to 1130 lb. in 1947 might have been attributable to competition between the increased number of fishing units employed in restricted areas. However, no such explanation could account the catastrophic fall in 1948 of both gross yield and catch per unit. Dr Blackburn, in supplement to his 1948 report, proposed a total closure in 1949, to be followed by catch quotas of 100 tons in 1950 and 200 tons in 1951 with continuing observations to learn the most satisfactory permanent level. In consequence, there was no open season in 1949 and the Sea Fisheries Advisory Board decided to be advised by Dr Blackburn on a suitable duration for the 1950 season. Thereafter, regulations were drafted by providing for an open season from 15th August to 30th November, with machinery provisions for earlier closure to be ordered by Gazette notice, should the proposed quota be reached earlier. When the proposals became known, there was strong opposition from canners to the suggested quota of 100 tons. Following discussions between their representatives and the Sea Fisheries Advisory Board, it was decided the quota for 1950 should be 375 tons. Such a quota amounted to a greater quantity than had been taken in any earlier year except one and was actually 80% greater than the average annual catch f 209 tons for the years 1943-1948, which has caused the collapse of the fishery. A reservation that if “upon examination, any signs of depletion are indicated, the Minister will take action…to terminate the season” was meaningless, in view of the notification to the canners at the same time of this high quota. Obviously, if 375 tons had been taken, it would have proved an abundance of fish. But until such a quota was reached, the canners could argue that the run was late and they were holding cases, tinplate, labels &c., which they should be permitted to use. (The word “quota” was not in fact used in the notification to canners, which referred, not to a maximum, but “optimum” catch). In fact, no action was taken at all under the provisions for terminating the season, although in 1950 the catch fell to 10% of that of 1947 and when thereafter the deterioration continued until, in this last five years, the average annual yield has been 12 tons, that is, about one thirteenth of the proposed quota, the catch per unit in the last two years has averaged 130 lb. as against 440 in 1948 and 1550 in 1946. Since 1950, changes in regulations have ad the effect of making still more effective the destruction of the remnants of the Northern whitebait population. (For other reasons that whitebait conservation the Forth was closed to whitebaiting, but its earlier contribution had amounted to only 4% of the total yield). The 1950 regulations prohibited the taking of whitebait between sunset on Fridays and sunrise on Mondays. This reservation was dropped in the 1957 regulations. The earlier regulations prescribed a closed seasons from 1st December to 14th August. The 1957 regulations provided for an open season from 1st August until 1st January. The extension by four weeks at the end is unimportant, as the run is greatly reduced by the end of October, but the addition of a fortnight in August materially reduced the period within which uninterrupted spawning had previously been possible. In 1960, over a third of the total catch was taken in August and summaries of monthly catches indicate the probability of appreciable runs occurring in July. Probably this pre-season entry is all that saved the stock from extermination, or delayed such a happening.

Trout and Whitebait
If trout had never been established in the Northern rivers and coastal waters of Tasmania, there would still be adequate justification for a total cessation of whitebaiting for a number of years to learn whether it is not still possible for this species to re-establish itself in sufficient strength to permit carefully regulated exploitation at some future time. However, as was learnt in 1949, when whitebait were very greatly more abundant than now, closure for a single season is quite inadequate to permit recovery. Whatever influence the introduction of trout may have had on the whitebait population, the facts are that the two species co-existed with a considerable overlapping range for nearly 80 years and that predation by the trout was never severe enough to precent the whitebait continuing in very great abundance. Dr A G Nicholls, in a general consideration of size and abundance of trout in fresh and tidal portions of Northern rivers, between 1945 and 1954, (Aust. J. Mar. Freshw. Res. Vol 9, 1, 19-59) made no direct observations on the food of trout or special enquiry into inter-relationships of trout and whitebait. However, he remarks that he did not find any “direct, consistent correlation” between the estuarine trout fishery and the commercial whitebait fishery. It is important that this statement should not be misconstructed as a statement that the estuarine trout fishery was not in any appreciable measure influenced by the abundance of whitebait or the whitebait fishing practice. Direct and consistent correlations are unlikely to be demonstrated by the relatively scanty data, especially when there is only a partial environment overlap and the predator species is very catholic in its feeding habits. Indeed, Dr Nicholls has been careful to how the abundance of whitebait could affect the availability of trout to anglers by bringing them into effective rand of shore-based anglers. He also demonstrated that the number of days devoted to angling in tidal waters by the typical angler dropped by half as the whitebait stocks fell off. The finding that such anglers as did fish tidal waters took much the same quantity of fish as formerly is not inconsistent. While there is no positive evidence that it is so, it is a logical and widely held belief that trout, which are present in abundance in coastal waters, follow shoals of small anadromous fishes into rivers and that the duration of their stay in tidal reaches is much dependent on the continued availability there of such small fry. Whether this is correct or whether the presence of concentrations of whitebait in marginal waters simply induces local inshore movement of trout, which would normally be lying deeper and more widely dispersed in the estuaries, is it not really important. It is beyond reasonable dispute that the presence of whitebait does induce trout to feed both vigorously and conspicuously at inshore points where the small fry concentrate and that thereby trout become readily available to anglers. Such concentration points (usually eddies offering some shelter from strong currents) appeal equally to whitebaiters and to trout. As the angler seeks the actively feeding trout, he comes into direct positional conflict with the whitebaiter. In the restricted estuaries of the Northern rivers, each with its limited number of good concentration points, the actual disturbance or domination of areas by whitebaiters can make angling relatively ineffectual, or, at the very least, very unattractive. To the angler, the whitebaiter is a source of direct interference with his sport, while the whitebaiter, I turn, suffers the annoyance of having the smooth movement of whitebait frequently disturbed by the feeding trout. No one who has observed trout feeding on whitebait would need to have his observations reinforced by analysis of gut contents, before and after the commercial whitebait fishery developed, to be convinces that the substantial destruction of the whitebait population has been seriously damaging to the trout fishery.

Conclusions
1. An indigenous species of fish, the whitebait, which a few year back was enormously abundant, has so diminished in numbers that recent commercial yield has been about 6% of what it formerly was.
2. Trout and whitebait had co-existed for nearly 80 years and the whitebait continued to be extraordinarily abundant until commercial exploitation started.
3. There is irrefutable evidence that the whitebait fishery has been substantially destroyed by gross over-fishing, which has continued, with increasing ill effects, for a decade after competent scientific enquiry had diagnosed the cause of the first sharp decline and recommended remedial measures. There has for 10 years been failure to attempt to arrest or remedy the continuing decline by exercising powers provided for that purpose in regulations made in 1950. Instead, the earlier regulations have been relaxed further to permit more sustained fishing during the former open season and an extension of such season.
4. The destruction of the Northern whitebait population may already have proceeded beyond the point from which recovery might be possible. Only the immediate and complete cessation of all exploitation in Northern waters for some years would appear to offer any hope of saving the whitebait population.
5. An incidental effect on the substantial destruction of the whitebait population has been the loss of a valued trout food. Such food has been of special significance in that it greatly increased the availability of trout in estuarine waters, thereby making for better fishing and less congestion in inland waters.
6. Whitebait fishing in the Northern rivers is the part-time interest of 65 persons. Trout fishing in the same rivers is the part-time interest of over 6500 local North-West Coast residents.

Recommendations
1. It is recommended that regulation 33 (3) of the 1957 Sea Fisheries Regulations be invoked at once and that a Gazette notice be issued closing all the Northern rivers to whitebaiting in the season which otherwise would be open on 1st August next.
2. That in view f the failure of the single closed season in 1949, to permit recovery of the stock, which was then in a very greatly stronger position, closure for a number of years now be contemplated. DF Hobbs, Commissioner. 30th June, 1961.

Sea Trout

Sea Trout are a bit of an enigma around the world. Runs of these brown trout, born in a river, migrating to sea, and returning to a river for feeding (or spawning in autumn), are notoriously hard to predict. But like searching for Lasseters mythical reef of gold, the thrill of the chase and the promise of big rewards (sight-fishing to double figure fish if successful), offers more than enough attraction for most of us fly fishers! Timing is all about recent rainfalls (the time between the wet of spring and the dry of summer is when things peak), and the availability of migratory food sources such as whitebait are key to success. There’s sea trout hotspots around the state: the Derwent, Huon and Lune systems down south are the most popular, with the Derwent offering months of sea-run fishing throughout its long and complex system, as migratory browns and resident slob trout follow runs of whitebait, lampreys, mullet and glass eels up and down the system from urban Hobart to rural New Norfolk. In the north and north east of the state, the Boobyalla and Ringarooma mouths are a hard-to access hotspot, while the Great and Little Forrester rivers have respected runs of medium sized sea-runners. Across to the West Coast and the Arthur, Henty and Gordon rivers produce the best runs of big trout, but also some of the most un-predictable. If fishing among ancient rainforests or rolling sand dunes, in large tannin rivers sounds interesting, then this is the coastline to follow. The classic BMS whitebait patterns are the most popular flies, though larger and bulkier flies work best when things are quiet. Eight pound leaders and size #2-4 Woolly Buggers, Zonkers and Fuzzle Buggers are the go, complete with rubber legs and coneheads if your serious about getting among the snags and tempting the ambush feeding trout when things are quiet.

Sea run trout tactics – Craig Vertigan

During the trout off-season I tend to spend a bit of time chasing bream, to continue getting a fishing fix, and spend time tying flies and dreaming about the trout season to come. It’s a time to spend doing tackle maintenance, stocking up on lures and dreaming up new challenges and goals for the trout season ahead. When the new season comes around I usually spend the first few months targeting sea runners. Sea run trout are simply brown trout that spend much of there lives out to sea and come in to the estuaries for spawning and to feed on whitebait and the other small endemic fishes that spawn in late winter through spring. Mixed in with the silvery sea runners you can also expect to catch resident fish that have the typical dark colours of a normal brown trout as well as atlantic salmon in some of our estuaries that are located near salmon farm pens. Living in Hobart it is quick and easy to do a trip on the Huon or Derwent and is a more comfortable proposition compared to a trip up to the highlands with snow and freezing winds to contend with.

wynyard jetty flatheadWynyard Jetty Flathead

48cm long sand flathead caught off the end of pontoon at Wynyard yacht club boat ramp. 735 grams was it's weight.

 

Click "Read More" for a full sized picture 

Marine Science Special Podcast

Deep sea climate change, enviro bags, over-fishing
It's a Marine Science Special! Professor Emma Johnson joins Dr Karl and Zan Rowe to help answer your ocean-based science questions.

http://www.abc.net.au/science/drkarl/scienceontriplej/

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