Category: Category Two 

SOMETIMES, just sometimes, tarwhine can be a pest if they are small and numerous. But if they are getting up towards a kilo in weight they can provide great fun and can be feisty critters indeed when hooked on light gear.

Anglers fishing from a dinghy in quite shallow water can often do well dropping a whitebait or blue sardine down near some likely looking rocky inshore reef. They tend to lurk where shore anglers would be dissuaded from casting for fear of losing their gear – whereas dinghy anglers can simply lower their bait right on the spot with little risk of snagging the bottom.

The West Coast and Gascoyne Region daily bag limits of 16 fish appear somewhat generous given that tarwhine are not the finest table fish as they can be quite soft when cooked.

Rhabdosargus sarba is thought to have an Indo-West Pacific distribution although West Australian researchers have raised some doubts about this.

Tarwhine are still commonly referred to in WA as silver bream.

Identification
At first glance inexperienced anglers can mistake tarwhine for yellowfin or black bream, but the best way to tell the difference is that tarwhine have 6-7 rows of scales above the lateral line and yellowfin and black bream have four.

Tarwhine generally have a silvery body with rows of yellow dots forming longitudinal stripes.

Another identifying feature is the forehead on tarwhine, which is convex, while in yellowfin and black bream the forehead tends to be flat or even slightly concave.

Size
Although the Australian Museum shows tarwhine growing to a very healthy 1.4 kilos and 45cm in length, some records even show the largest tarwhine at a massive 2.44 kilos and 52cm in length.

Most anglers would be delighted with a fish of over a kilo, but tarwhine would mostly be encountered at something closer to half a kilo in weight, and sadly many are much smaller than that…

Distribution
Tarwhine can be found in estuaries, along surf beaches and on inshore reefs up to 35 metres in depth, from Albany through to Coral Bay.

Breeding and migration
Tarwhine are pelagic spawners and spawning occurs from July to November in estuaries and inshore waters. In the Swan River spawning occurs in the deeper sections of the river, generally during strong ebb tides and times of high salinity, which carry the eggs downstream to the ocean. These tarwhine do not re-enter the estuary until they are at least one year old.

Tarwhine have been shown to undergo size-related movements, starting off by settling in sheltered, sandy surf shorelines. From there they move progressively to nearby seagrass beds and then to exposed sandy surf shorelines and finally they move out to areas around inshore reefs where ocean spawning occurs.

Small crustaceans comprise most of a tarwhine’s diet, but as they get older they change their diet to become herbivorous.

Interestingly in the lower reaches of the Swan River, and in Shark Bay, the length at which half of the fish reach maturity is approximately 180mm. However, in coastal marine waters near Perth, the overall size at maturity is 230mm. In the marine environment, tarwhine attain maturity once they move to the inshore reefs, where during the spawning season tarwhine only 180mm long were mature. Conversely in the shallow shoreline waters, fish up to 250mm were not mature! As you can imagine, this might have important management implications, because it effectively means that all tarwhine caught on sandy surf beaches (but not those with reefs) are immature. Tarwhine have been recorded as attaining a maximum age of 13 years.

At Murdoch University a study by Dr Alex Hesp showed that, in WA, tarwhine were unquestionably a rudimentary hermaphrodite. That is, a fish that starts life with indeterminate sex (they contain gonads with both female and male tissue). With increasing size/age, the fish become either females or males (no sex change). However, this species has been clearly shown to be a protandrous hermaphrodite in Hong Kong, which means fish start life as males and change sex to become females. The study in South Africa on this species also came to the conclusion that it is a protandrous hermaphrodite (but that not all individuals change sex). This raised the question as to whether tarwhine (Rhabsosargus sarba) in WA were the same as elsewhere.

Threats
Over-fishing does not seem to pose a threat at this time, but environmental issues with the associated decline in water quality and water flows in all of our southern estuaries could become a problem. Only time will tell.

Tackle and bait
Tarwhine should be targeted using light tackle, if the best sport is to be had. A medium spin outfit loaded with 6-8 kilo line would be fine. A longish rod of around three metres is useful in order to keep the line above the shore break and to provide the best control when a fish is hooked.

Terminal tackle can also be as simple as a couple of metres of 10-kilo mono trace with a running ball sinker down to a small set of gang hooks for whitebait and blue sardines, or a long shank single hook for prawns. Small strip baits can also work well for tarwhine at times.

In stronger surf locations, where a larger sinker is required, the best terminal gear is a single dropper loop rig.

Fishing methods
In some locations tarwhine like a rising tide as it tends to provide them with the feeding opportunities that they are looking for as the tide washes over shallow reefs and gutters. Some white water over the reef structure also improves your chance of finding a tarwhine. In other locations low tides can provide the opportunity to fish reef holes and ledges that are not readily accessible at high tide.

Southern surf beaches also turn up their fair share of decent size tarwhine and they can be found feeding in gutters, especially at night. Indeed, early morning and evening are generally the best time to catch tarwhine.

A long cast is generally not required when targeting tarwhine, as many good fish can be found very close to the beach. Use a series of well-placed casts to explore a particular location and if nothing is found move on to the next likely looking spot. Travelling light and walking the beach is the best way to fish for tarwhine.

When beach fishing think like a fish and try to place your bait in a natural fish highway, like sandy gutters and holes adjacent to any reef structure. If there is no reef visible then concentrate on fishing the beach holes and gutters.

References:
Sea Fishes of Southern Australia by Barry Hutchins and Roger Swainston. Stud South Coast Silvers by Tim Gray (Western Angler Feb/Mar 2006) Compiled with the assistance of Dr. S Alex Hesp, Murdoch University.
Fishbase website  www.fishbase.org