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Algal blooms at bay
  |  First Published: November 2012



This is the time of year when Australians flock to the beaches, the surf is at its cleanest, and with every hot day come fears of the surf along Teewah Beach and Fraser Island turning brown with the annual algal blooms.

So far there has only been the occasional sign of algal presence, which has quickly been killed off with regular cool southeasterly wind changes that deposit the dead algae on to the beach to disappear under the wind blown sands.

We are all hoping that this pattern of regular southeasterly winds continues to keep the algae at bay, but in reality, there is little likelihood of an algae free summer. Over the past 11 years, the worst algae outbreaks have occurred during periods of high temperatures and low rainfall associated with El Nino events that was at its peak between 2000 and 2008.

The La Nina weather pattern of the last few years has delivered healthy wet season and winter rains, regular southeasterly trade winds and cooler average temperatures, all of which contribute to reducing algal proliferation.

Very little has changed on the fishing front on Teewah Beach since last month with catches still few and far between. However, there has been the odd tailor caught, and although small, these fish are more than welcome when we were all beginning to believe that we were to miss out entirely this year.

For those prepared to put in the hours, a few whiting, bream, dart, flathead and tarwhine can also potentially be found and a feed to be had. Persistence is the key with moving from gutter to gutter to find fish proving to be essential practise.

Last November was memorable for the number of flathead that were being taken from the gutters all along Teewah Beach. I doubt if I have ever seen as many taken in all my time at Teewah. Most success was gained by using half pilchards on a gang of 2 hooks and by moving from gutter to gutter to locate the fish. Some anglers were also getting excellent results on plastics retrieved through the shallow gutters close to shore.

Also memorable at the time was the lack of any other species being taken, which caused the flathead to become the major target. I fully expect that this November will be very similar in this regard.

commercial catch statistics data

While I have been very focused on the science associated with fish behaviour in relation to netting activity, I have had little factual knowledge of what returns the net fishers themselves have been attaining over the years other than anecdotal reports. So, in order to establish exactly how well the pros have been faring over the years, I recently purchased from Fisheries Queensland the commercial catch statistics data for Cooloola and Fraser Island.

I must admit to initially being very surprised at how high the numbers were for most of the conventional target species and how consistent catches have been over the past couple of decades. But with the help of Microsoft Excel and the ability to construct graphs of the catch data, including daily averages per licence holder and rainfall totals, a pattern for each species began to emerge.

Without considering the improved efficiencies of the commercial operators that have taken place over the years and the knowledge that such efficiencies can artificially inflate catch totals, the general trend of catch totals over the years is a marginally downward one. And although the data received from FQ nominates the days fished to achieve the catch totals, it doesn't include the days when searching for fish occurred but no fish were taken. It is reasonable to assume that with a reducing biomass of target species that has been occurring over time, that more time is spent by the pros searching for fish in recent times than would have been the case 20 or 30 years ago.

The total catch of tailor for the netters in 2011 from Teewah and Rainbow Beach was around 3.5 tonnes, but the days fished nominated by the FQ data only includes the days when tailor were actually caught and doesn't include all those days searching and when the nets remained dry. This in itself provides a misleading representation of the K8 tailor fishery, although a grand total of 3.5 tonne between 10 licence holders speaks volumes on it's own when 2010 produced over 30 tonne.

Also apparent from the graphs of total catch data compared to the average catch per day per licence holder, is the reducing average per day that each licence holder is attaining compared to the catch totals. This, without considering the days when searching occurred and nets weren't shot, reflects a situation where the netters are working harder for smaller returns which is a critical component associated with fishery assessment and management. Catch Per Unit Effort (CPUE) is used in all fishery management to assess the health of a species' population. A decreasing CPUE, as can be determined from the data, indicates overexploitation of the fishery, whereas an unchanging CPUE indicates a sustainable fishery.

Relevent also for tailor as an indicator of an overexploited species, is their documented reduced size at age and altered migration compared to the 1970s. Reduced size at age, or in other words, smaller now at a given age than they were in the 70s, is a certain indicator of a species that is overfished. The northern spawning migration of tailor has for some years now been determined by FQ to be more offshore than was the case in the 70s. This is expected to be as a result of inshore fishing pressure causing avoidance behaviour by the tailor with, as has been determined for other collapsing fish populations, ramifications to feeding and spawning success. When 80% of legal sized tailor are anticipated to be harvested each year by either professional or recreational fishers in SEQ, this avoidance behaviour is to naturally be expected.

Very apparent in the graphs, and stated by Fisheries Queensland as being the case, is the obvious correlation between catch totals of each and every species and the total annual rainfall. Generally, the higher the rainfall, the larger the catch. It can be interpreted from the catch data and rainfall figures over the last decade, that high rainfall in recent years has enabled healthy returns for the pros which also enabled reducing fish populations to appear to be reasonably healthy. That is until 2011 when good rainfall is not mirrored by good catches, with catches of all species in fact deteriorating noticeably in comparison to the rainfall.

What should be of great concern to fishery managers, and all of us, is that we are now entering an El Nino phase which is expected to deliver below average rainfall and above average temperatures. With this year's mullet catch for Cooloola said to be the worst on record and the noticeable downturn in catches of all species following what we all know to be a year of high wet season and winter rainfall, the prognosis for commercial catches for the period of this El Nino can safely be said to be very poor for all species. Add the expected increase in the incidence of algal blooms associated with El Nino, and there would appear to be a horror stretch ahead for both commercial and recreational fishers. Many of the pros are already stating that things are bad and you wonder how they, and the fish populations, are to withstand the years ahead.

It won't just be the fish that will struggle through this period. This year has seen very large numbers of juvenile gannets dead on the beach. Gannets time their breeding to coincide with the northern spawning migration of tailor. This is because tailor schools herd baitfish to shallow water or to the ocean surface where the gannets, as well as other seabirds such as terns, can access their prey. No tailor, or other predatory species that herd baitfish such as trevally and dart, can only mean that feeding prospects for seabirds are dramatically reduced. So much so, it would seem, that survival of juvenile gannets in particular, may not be possible if the predatory fish species are not present in sufficient numbers. Migratory and sedentary tern surveys conducted inside the mouth of the Noosa River each month since 2004 have shown a halving of their numbers in those 8 years.

There is no good news associated with the inshore fisheries of any of South East Queenland's coastal regions. The same things are occurring all along our coastline and there are no plans by this government to alter anything that may assist any sort of recovery. In fact, this is a statewide issue that effects every Australian. We can sit back and allow our governments to do nothing from term to term and watch the mess unravel, or we can be proactive in demanding better from those responsible for maintaining our fisheries and native wildlife. 'Better', is a strategic network of net free regions all along the Queensland coastline with reduced bag limits and increased size limits for species taken by anglers in the net free regions. I am active in my attempts to demand better, but what are you doing?

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