Batfish Sneak Up On Scientists

I've been studying a lot about herbivorous reef fishes lately because, as it turns out, they have some similarities with turtles in the role they play in maintaining reef systems, ie, they make sure that the garden doesn't become overgrown by grazing on all the growth. Along the way I came across a fascinating paper (Bellwood et al, 2006) which appealed to both my interest in reef systems and to my delight in watching the environment turn scientists on their head. Before I explain the story, bear in mind this is drawn from an extensive scientific paper which discusses many other ideas and concepts and I have simply drawn this thread from the bigger picture to illustrate a point, okay? Okay, here we go.

So… these marine scientists were looking at what might happen to coral reefs after they die, which they've all come to accept is inevitably going to happen. They expect that once the coral is dead, the algae will have a better chance for space and the herbivorous fishes will have a field day. They call this a 'phase shift' from coral reef to algal reef. To test their theory, they take a closer look at a coral reef, identify about 43 species of herbivorous fishes they expect might take part in the process given that they are already doing the onsite herbivory job and they experimentally induce a large scale phase shift to the area.

But something happens that they didn't expect. The 43 herbivorous fishes weren't the ones most responsible for eating all the extra algae. The fish that did was not even on the list. To their surprise, most of the phase shift reversal work was outsourced to a single batfish species (Platax pinnatus) which was previously thought to feed at “No Spines”, the local invertebrate eatery.

The results show that the environment is an amazing and complex system which can and will recover from disturbance in ways you had never considered were possible. Human induced disturbances to wild fauna populations such as over-harvesting, even at a local scale (I’m looking at you Margiris/Abel Tasman) will also have effects the world’s leading scientists cannot predict now, or in the future.

Tread lightly.


Reference:
David R. Bellwood, Terry P. Hughes, Andrew S. Hoey. 2006. Sleeping Functional Group Drives Coral-Reef Recovery Current Biology, Volume 16, Issue 24, 19 December 2006, Pages 2434–2439
http://dx.doi.org/10.1016/j.cub.2006.10.030

Sea Turtle Health & Rehabilitation Workshop 2013

There has been marked increase in the establishment of sea turtle response centres on the east coast of Australia in the past five years. Back then, when I started as GM of a centre in Ballina, there were only five centres of our kind across the country. Being the huge continent we are, and the tendency of sea turtle work to be all-consuming, the managers, vet or volunteers at the centres were not really connected. That was until the Sea Turtle Foundation and James Cook University hosted the first sea turtle health and rehabilitation workshop in Townsville in 2011 (and managed to make it affordable). So off I went back to my old college town to represent our facility and share some pictures with other sea-turtley people. I found the presentations fascinating. Sea turtle health and rehabilitation issues are wide ranging and constantly under review. From husbandry and quarantine, rescue response, nest monitoring, veterinary case studies and round table discussions, around 100 people now gather for discussion and debate each year.

Image copyright ASR

This year, the 3rd sea turtle health andrehabilitation workshop stretched over three days and included seminar sessions on health, habitat and rehabilitation and field trips around the beautiful Townsville region, including a morning on the stunningly beautiful Magnetic Island. The Magnetic Island Network for Turtles (MINT) gave a short presentation and a guided tour detailing the early development of their sea turtle rehabilitation centre blossoming out of an old local council pump station in Horseshoe Bay (kudos to the Townsville City Council for the land). Already streets ahead of our first turtle rehabilitation ponds back in the late ‘90s, the community support for MINT is reminiscent and undeniable. I bright future there, I see. 

The community here on the east coast of Australia (at least), expect that we should invest time and effort into rescuing and rehabilitating all kinds of wildlife. They may not be too fussed about the snakes and spiders, but sea turtles and koalas definitely have a marketing edge and it is very rare that calls for help with infrastructure and construction of these community projects are not met swiftly.

Hawksbill turtle strandings in NSW 1998 - 2011*

Seasonal variation of Hawksbill stranding events in NSW (1998 - 2011)*

Latitudinal variation of Hawksbill stranding event in NSW (1998 - 2011)*

Nowadays sea turtle triage and rehabilitation centres are popping up all over the coastline in backyards of homes, businesses and zoos, wherever the need has been identified. I suspect the increase in people willing (or needing) to respond has been in response to what attendees at this year’s workshop comfortably and repeatedly referred to as “The Starvation Stranding Event of 2011” (see figures above), which saw a marked increase in sick turtles both in real life and in the media. Several of these centres are now sitting empty, and I strongly suspect that the number of response centres will contract in the coming years now that the stranding rates appear to be returning to ‘normal’. 

Hart et al (2006) suggested from drift bottled experiments that only 20% of turtles that die at sea reach the shoreline. If I conservatively applied that theory to the stranding event I witnessed in Northern New South Wales in 2011, this could suggest that around 350 Hawksbill turtles starved to death in that region, not just the 72 that we saw wash up on the beach. It’s never been more imperative to go out into this area to identify and assess sea turtle habitat in the Tweed-Moreton Bioregion.

*unpublished results

The Glowing Dolphins - A Trans-Atlantic Treat

A few years back I was working as crew on private yachts sailing around the edges of the Atlantic ocean. Back then there was an abundance of work both delivering bare-boats and crewing high-end charters. For the most part the owners of vessels from 20ft to 362ft long kept me out of trouble scrubbing decks and serving Cristal champagne to the guests (and myself in the stew pantry) in Ports and at sea anywhere and everywhere between Florida, Trinidad and Italy. It was a good, healthy life that I reminisce about often. Footloose, fancy free and moving with the flow of work which had me reaching for my passport on a weekly basis, I had racked up around 7,500 nautical miles in 12 months. Most of that mileage is attributed to a trans-Atlantic crossing from St Maarten to Antibes, France.

Azores - Your Logo Goes Here

Mid-Atlantic Sailing

For weeks we saw nothing but blue-water horizons. Occasionally a freight ship would thunder past but other than that the weather advisory services kept us on track for a very smooth and uneventful crossing. The order of the days rotated around your watch-keeping duties, sleep and other sanity-maintaining entertainment like movies, card games or fishing. All the excitement was left to the wildlife watching. At any moment you could hear a watch-keeper shout “WHALES!” or “DOLPHINS!” which would send the off-duty crew scrambling for their cameras and up on deck to hang over the bow taking pictures and soaking up the awe. There is no doubt about the impact wildlife have on humans, as well as the impact humans have on wildlife. Sailing around the Azores, where we stopped for a mid-crossing drink, was filled with encounters with whales and lots of scrimshaw.

From the Azores we headed towards mainland Europe for my first time. Clear blue skies were slowly turning dull and grey. Each day as we approached the Gibraltar Straight this seemed to be getting worse and it ended up taking me about three days to figure out what it was. It was the smog from the mainland. I did't want to go there, really. We charged on through the guts of the Gibraltar Straight which was like a 16 lane wide super-highway where the confidence of Captains and crew are put to the test. I was on watch that night with the Engineer and all I wanted to do was simultaneously scream with exhilaration and crawl into a corner of the deck and cry as colossal freighters and cruise-liners lit up like Christmas trees towered over our 110ft sailboat as we battled for our space in the parade. Unbelievably, there were tiny little boats running across the flow between the headlands of the straight, a very high risk game of chicken which they had no doubt been doing for generations. On the interior of the Mediterranean it was finally time for me to sleep.

In the darkness, out the porthole of my cabin, I could see the wake of the boat being highlighted with bright streamers of bioluminescence. It was the most magical thing I had ever seen, I thought. That was until I saw the dolphins. As they raced through the water alongside our boat they left long tubes of bioluminescence behind them like vapour trails through the inky water. From above deck you could see the dolphins coming towards the boat from about 50m away to race up alongside and jump out of the bow-wave coated in the glowing water. I was nearly wetting myself with excitement. An occasion in the Caribbean where our boat sailed through a smack of flashing jellyfish comes a close second in my all-time favourite wildlife experiences.

One must feed one's self

The next day, still riding high on the excitement of last night, I again raced up to the deck with camera in hand to the call of whales. In the distance it looked like a pod of black whales on the move, bobbing up and down in the swell as they take their breath. The deckhand and I raced to the bow to photograph the amazing event when the reality of our geographic location hit us both like sledgehammer. You’re in big lagoon now, essentially, with human population on every border. They weren’t black whales, they were around 40 black storage drums, dumped at sea, bobbing around in the waves. Wave as you go past, this won't be the only pollution you see through the haze.