Category Archives: Reef fish research

Parrot Fish Frenzy

Yesterday the GVI marine team swam transect 10 for only the second time this year. This transect is located on the South-East side of Kisite Island and is therefore inaccessible for much of the year, when we have strong winds and rough seas.

The transect was very interesting and whilst quite close to transect 9 it was also quite different. The coral substrate was very healthy and there was a variety of reef fish that we haven’t observed elsewhere. Noticeably, there were lots of parrot-fish, both individuals and variety of species.

Scaridae Cetoscarus bicolor juvenile

Scaridae Cetoscarus bicolor juvenile

Parrotfish (Scaridae) are a common site on most coral reefs and feed on algae, coral and sea grass. Unlike other reef fish, individual parrotfish species have specialised diets meaning that they don’t compete with other parrotfish species for food. Parrotfish do not have a true stomach and much of what they eat returns to the reef as sand- it is thought that larger species can deposit up to 5000 pounds of sediment in a year! They vary greatly in colour, the females are often dull and the males brightly coloured, although they are hermaphrodites and can change their sex and colour depending on what phase they are in which makes identifying them a challenge!!

Scaridae Hipposcarus harid

Scaridae Hipposcarus harid

We have taken numerous photos which it is hoped will help us to identify which species we have not seen before. In the meantime we will continue to snorkel transect 10 as much as we can.

Rachel Zabari – December 2010

Some information taken from  Allen et al. 2003, Reef Fish Identification- Tropical Pacific

New transect brings new data!!!

Our marine programme has had a recent addition that we are all very excited about!!! Transect 11 has just been added to our snorkel surveys. The transect is just off the shelf outside our Mkwiro base which means that as long as the tide is low it can be snorkelled without even getting on a boat!!

Carrying out the snorkel transect underwater surveys

Carrying out the snorkel transect underwater surveys

 The transect has already proven to be very interesting, with some species seen here that we haven’t seen on our other transects. Bottlenose and Humpback dolphins have also been recorded off the eastern end of the transect. Other interesting species seen on this transect include large Barracuda and Hawksbill and Green turtles.

Interesting species are surveyed such as this amazing Lionfish

Interesting species are surveyed such as this amazing Lionfish

This data proves that although the waters in the Wasini channel are not protected by any jurisdiction they still offer an abundant and diverse range of sea life that we hope to be able to monitor and over time, preserve with the help of organisations like KWS who share our data.

Update on Reef Fish Surveys

Three months and one expedition on from the start of the new reef fish surveys and 21 surveys have been completed on six different transects, recording over 4000 fish.

The most abundance and diversity was found within the Kisite Marine Park, with the average number of fish recorded per day exceeding 500!! The Wasini channel on the other hand averaged less than 5 fish a day. There may be a number of reasons for this, the primary one being that no type of fishing is allowed in the marine park, whereas many means of fishing are allowed in the Channel.

The next step is to obtain more data from the channel as a recent snorkel trip off the reef in-front of our base in Mkwiro indicates that there maybe more in the channel than we first thought. During this trip four new species were added to our catalogue, including the Piccaso Triggerfish. Adding new fish to our catalogue is exciting as it is photographic evidence of the diversity of fish found in the waters of Southern Kenya.

Balistidae Rhinecanthus Aculeatus

Balistidae Rhinecanthus aculeatus

The information we are obtaining is particularly important due to the commencement of seismic surveys in the area this September. Seismic surveys have the potential to disturb fish and fish larvae. The disturbance would likely show initially with the bigger species of fish leaving the reef and moving somewhere else. Therefore the data we record over the next expedition will be both interesting and also very important!

Beautiful Bony Fish

The class Osteichthyes (Bony Fish class), where 90% of all the living fish are, within the Teleostei order represents more than 27,000 species, and a great part of this number are reef fish species. This classification (Bony fish) is given because of the lightweight and strong skeleton. Their distribution is so vast, they are found in almost all marine habitats.

In the order Teleostei the most common species known by the general consumer are the Tuna, Cod, Halibut, Goldfish, etc. These fish have distinct morphological features that brought them huge success to this class, like movable fins for well controlled swimming at great speeds avoiding predators or to pursue the prey. One really important advanced feature is the gas-filled or fat-filled bladders that provide the effectiveness of the buoyancy in to the water-column.

Boxfish are examples of bony fish

Boxfish are examples of bony fish

In the reef world we have beautiful colored fish, this can be explained by the use of colour – or colour patterns – for concealment.  This camouflage effect can be best described as a cryptic colouration; that is it matches the background colour against which the fish habitually lives. The magnificent colours are produced by thousands of pigment cells in the skin called chromatofores, these cells contain melanin pigments that give the brown or black colours, or the carotenoids pigments that give the yellows, orange and red to the fish. In addition to the chromatofores we have the iridocytes that are reflecting cells, this reflecting cells have an excretory product called guanine, greatly increasing the range of colours.

Colours and patterns are used for camouflage, sexual display and territorial behaviour

Colours and patterns are used for camouflage, sexual display and territorial behaviour

Scientists explain the huge range of colours in the reef fish community by the enormous biodiversity in the reef ecosystems; the colour patterns thus make recognition certain, particularly between closely related species. In addition, the colour and colour patterns serve to stimulate successful meeting and the chance to cross-breeding and so maintain species in breeding isolation and they amplify the effects of displays in territorial behavior.

 

References

  • Essentials of oceanography, Fifth Edition, T.Garrison, 2006
  • A Guide to common reef fishes of the western Indian Ocean and Kenya coast, K.Bock, 1992

Gems Of The Sea Expand Reef Fish Catalogue

The reef fish catalogue, by definition, is an easy way to visually represent what kind of fish biodiversity we can see in our transects inside the Kisite-Mpunguti Marine Protected Area.

It was started during previous expeditions, and now with our marine biology backgrounds we think we can continue the work on it and move it forward.  In fact, this “work” is something that gives us a lot of pleasure (how many people can say that?).  The methodology is simple; we simply traverse our transects within the KMMPA, and take pictures with a Canon Power Shot D10, underwater camera. The aim is to take a picture of the fish that shows the full body, usually the flank plane, to allow it to be easily identified using the reef fish species book. Normally these flank shots show us the main features of the fish including colouration, body shape, tail and fin shapes, markings or identifying features.

Indian Redfin Butterflyfish

Indian Redfin Butterflyfish

This enthusiastic project involves the collaboration of all the GVI marine team based on Wasini Island; staff and volunteers. Each time we get into the water everybody wants to get more pictures of species that aren’t yet catalogued, as the desire to improve our catalogue is strong!

Titan Triggerfish

Titan Triggerfish

With the catalogue we will be able to identify which species of fish we have on each transect and do a comparison between species of the Marine Park and Marine Reserve. This data can be passed onto Kenya Wildlife Service with the potential to assess the effectiveness of current management strategies. We also plan to give out laminated copies to the tourist boats enabling them to identify species themselves and to educate the tourists about which interesting species are found here.  It will also add to their snorkeling experience!

Treadfin Butterflyfish

Treadfin Butterflyfish

The final aim for the project is to complete regular snorkel surveys with dive slates that will have species names and size estimations. The group to start this long term project is already here carrying the enthusiasm, skills and the will to keep developing it. Everyone wants to see what the final product of this interesting, fun, yet challenging project will look like.  To us – a catalogue of this underwater dream world!

More news about this subject will come soon.  REEF FISH RULE!!!

 Fred & Julien (GVI Marine team)

Under The Sea

Reefs are the dominant habitat around tropical shorelines, considered the Rain Forest of the Sea, being highly productive due to the efficient recycling of nutrients and the high levels of biodiversity they support. Coral Reefs are found throughout tropical waters where water temperatures are in a range of 20-30C. The diversity of coral species provides a vast array of microhabitats, refuges and food sources for a high diversity of other marine organisms. Coral Reefs are thought to support one third of all living fish species.

Clockise; Star puffer fish (Arothron stellatus), Clearfin Lionfish (Pterois radiate), Guineafowl Pufferfish (Arothron meleagris), Blue triggerfish (Pseudobalistes fuscus)

Clockise; Star puffer fish (Arothron stellatus), Clearfin Lionfish (Pterois radiate), Guineafowl Pufferfish (Arothron meleagris), Blue triggerfish (Pseudobalistes fuscus)

It is estimated that 10% of Coral Reefs have been degraded beyond recovery by human activities. From the information gathered in the last STATUS OF THE CORAL REEFS OF THE WORLD: 2008, in Eastern Africa 15% of the Reefs are considered effectively lost and are unlikely to recover soon.

Region Coral Reef Area km2 Effectively Lost Reefs (%) Reefs at  Critical stage(%) Reef at Threatened stage (%) Reef at Low threat stage  (%)
Eastern Africa 6800 15 22 28 35

 Taken from Status of the Coral Reefs of the World 2008

The major threats concerning this ecosystem include:

  • The Indian Ocean Earthquake and Tsunamis of 2004
  • Plagues and Diseases
  • Continuing human stress on Coral Reefs
  • Global Climate Change
Clockise; Striped Surgeonfish (Acanthurus lineatus), Morish Idol (Zanthus cornutus), Semicircle Angelfish (Pomacanthus semicirculatus), Yellow boxfish (Ostracion cubicus)

Clockise; Striped Surgeonfish (Acanthurus lineatus), Morish Idol (Zanthus cornutus), Semicircle Angelfish (Pomacanthus semicirculatus), Yellow boxfish (Ostracion cubicus)

The Kisite Marine Park in Southern Coast Kenya is the biggest marine park in Kenya, with 28 kilometers square and still holds a very important Coral Reef Ecosystem. Every day GVI marine team snorkels the area  (we have currently three snorkeling transects around Kisite Island) trying to record and photograph the marine biodiversity and trying to access marine turtles habitat distribution. As an overall project objective, we hope to improve the scientific basis for the management of KMMPA (Kisite Mpunguti Marine Protected Area) by KWS (Kenya Wildlife Service) and identify potential conservation issues that should be addressed through management action and research.

Clockise; Brown marbled grouper (Epinephelus fuscoguttatus), Blackspotted Moray (Gymnothorax favagineus), Bluespine unicornfish (Naso unicornis), Coral Reefs, PowderBlue Surgeon fish (Acanthurus Surgeonfish).

Clockise; Brown marbled grouper (Epinephelus fuscoguttatus), Blackspotted Moray (Gymnothorax favagineus), Bluespine unicornfish (Naso unicornis), Coral Reefs, PowderBlue Surgeon fish (Acanthurus Surgeonfish).

Snorkelling in this Rain forest of the Sea and witnessing the beauty and amazing biodiversity, colours, shapes and perfect equilibrium of this fragile ecosystem, is a privilege and leaves no one indifferent to the importance of its protection and conservation. Enjoy these photos taken over the last two weeks!

The Elusive Humpback

I was sitting outside the cottage discussing the different types of hornbills found in Kenya, as a Trumpeter Hornbill had just flown over head, when Sergi (the marine officer of expedition 094) pulled me aside to talk about my independent project. I was secretly chuffed that I got given the one I did, as there was a choice of three. The title of my project was “Data Analysis of Indo-Pacific Humpback Dolphins (Sousa chinesis) collected by GVI Kenya Marine Team from 2006-2009.”
 HBD sightings

These animals are very shy animals and are not as well known as the bottlenose dolphins. Maybe because they are shy or perhaps because of their habitat distribution, there is very little data available. So this was a great opportunity to be able to provide some information. The GVI Marine Team has been collecting data on them since 2006. Whilst out on the boat on a survey day, if we have a spotting we follow them around, taking photos and also monitor their behaviour. Using a GPS (Global Positioning System) we are able to plot the route taken by the dolphins that day.  This allows us to see the areas where the humpbacks dolphins feed, rest, socialise, breed etc. As well as being able to gain data on group sizes and composition.

 So I went forth and did some research on our friends the humpbacks and also plotted the information on our study area (see picture) which is the Kisite-Mpunguti Marine Park and Reserve and the surrounding area.
 Humpback dolphins occur in small groups (3-7) and are distributed throughout Indian and Western Pacific oceans as well as the coast of south east Africa. Inhabiting tropical and subtropical waters (15oC – 20oC), they prefer coasts with mangroves, rocky reefs, estuaries and lagoons. Typically found in waters less than 20m depth, they only venture a few miles from the shore line (as shown on the map), and occasionally they swim up rivers. The distinctive hump on their dorsal fin gives rise to their name; and they are medium sized 2.5m – 2.8m.
 

boat trWasini channel and the surrounding waters are prone to quite a lot of boat traffic and fishing. Humpbacks tend to avoid boats, although marks caused by propellers have been observed. This is a concern not only because of the damaged caused to the dolphin but also because of the resultant change in their behaviour, e.g. leaving the area. Another concern is that being situated on the coast; the communities living here depend upon fishing as a resource. Recent efforts have been made to educate some of the local community as to the importance and implications of over-fishing and pollutants.

 HBD spyhopping

It is my aim to develop a catalogue of the humpback dolphins, as this will allow us to determine population numbers and residency rates in this region. This is a technique called mark-recapture, and it uses the dorsal fins to identify each individual, mostly from the notches made by other dolphin or boats, but also by the shape, colour and size of the fins. Plus, on the cheeky side I will get to name some of them!

Sarah Watson was a conservation intern on 094 Expedition, and is currently doing her work placement with GVI, as staff member on the Marine and Terrestrial Programmes

The Importance Of Snorkel Transects In The Kisite-Mpunguti Marine Protected Area

Although dolphin surveys are a big and important part of the Marine Programme in GVI Kenya Expedition, the Turtle snorkeling transects are always one of the highlights of the marine day.  There are 7 transects set up within the Kisite-Mpungutti Marine Park and everyday the marine team snorkels along a 400 meter transect  searching for sea turtles and taking underwater pictures in order to assess the abundance of several reef fish families within the Kisite-Mpunguti MPA and surrounding area.

angelfish-blog.jpg 

 Angelfish

Kisite-Mpunguti Marine Protected Area (MPA) is the largest marine park in Kenya (28km²) where as the adjacent Marine Reserve is the smallest in Kenya (11km²). Inside the Marine Reserve traditional fishing methods are allowed, but the MPA is a safe haven for reef fish as both breeding and nursery grounds, protected from being exploited by fishing.

coral-reefs-in-the-mpa.jpg 

 Coral reefs in the MPA

Previous studies have shown that the abundance of some Indication species is ten times higher in the Marine Protected Area than in the Reserve.  However, little research has been carried actually been carried out in the MPA and surrounding area.  Therefore reef fish surveys are carried out to assess the abundance of several reef fish families within the Kisite-Mpunguti MPA. This data will also be used to assess the impact of fishing on the Kisite-Mpunguti Reserve in comparison to the MPA

emperor-angelfish.jpg 

 Emperor angelfish

We are currently training volunteers on different reef fish families that were showed to be relevant in terms of studying coral reef health. These groups include Indicator species, such as Butterfly and Angelfish families, which refer to species whose presence demonstrate a wider set of species and in turn greater biodiversity. The second group includes Carnivore species such as snappers and groupers which belong to a high trophic level and have high fishing value. The third group includes Herbivore species such as parrotfish, with medium fishing value. Volunteers are also trained on estimating the size of the fish observed to be able to find length frequency distributions of the specific reef fish families studied.  

green-turtle.jpg 

 Green turtle

The Underwater Visual Census involves two observers traveling slowly along a 50m transect, at a distance of 5m from one another.  Using a pencil and slate the volunteers will count and estimate the size of the reef fish species observed. 

snorkle-transects.jpg

Snorkel transects

Monitoring The Health Of Kenya’s Reefs

My name is Aaron. I am a conservation student from England. I have joined Global Vision International (GVI) as a conservation intern to gain experience in the marine biology field. I have been with GVI for 9 weeks with a further 11 weeks to go.
This week on Marine represented a new opportunity to expand GVI’s research in Kenya. The majority of GVI’s marine research has concentrated on monitoring tourist and fishing activity against dolphin behavior and abundance. Whilst this research has been, and continues to provide essential data to Kenya Wildlife Service, it is only focused on the effects to cetaceans.

reef-fish-surveys-transect-6.jpg

Setting up the survey 

This week we were able to begin monitoring reef fish abundance, with the intention of creating a long term data capture, similar to that of the dolphin surveys. This means that not only will we be able to see effects of tourism and fishing on dolphins, but we will also be able to see the effects on not only reef fish, but also coral reef habitats as the abundance of reef fish can indicate the health of reef habitats, which also act as feeding grounds for dolphins.

The way reef fish surveys are done is by sampling 5 random sections of coral reef habitats. Reef fish species and size are noted down. This gives a snapshot of the reef fish abundance at any one point in time and provides data on an exciting and important aspect of the marine ecology of Kisite-Mpunguti Marine Protected Area. It’s an honour to help set up this research and I am proud to be contributing to something that can make a real difference.
felicity-on-the-reef-fish-training.jpg

Survey training underway