Amazon Adventures Chapter 3

The Ayapua works up river throughout the year during the different seasons and where she moors is always dependent on the river level. We were visiting during the dry season and then it is not always possible to go beyond the river mouth that we were heading for. On this occasion, the river was high so we travelled further up river to tie up at a Ranger Station that we had not expected to reach. It was good to be there as it sited us nearer the survey areas and so less time was needed travelling in the small boats before the surveys could commence. The Ayapua was driven into the thick mud alongside the Ranger Station and tied up. A narrow gangplank was laid across to the steps leading up to the station. 

As the water level was unusually high, evidence of climate change, a large pole was driven into the mud at the side of the boat and the present water level marked with red tape. This needed to be checked every  day as if the level fell, we would have to leave to avoid being stranded.

Before I get to the point where I introduce you to the amazing animals we met, not least the pink dolphins that really are pink, I need to explain the survey systems, how they are carried out and what their purpose is.

We took part in three different types of surveys – Indicator Species Surveys, Resources Species Surveys and an ecological study in relation to climate change.

Dolphins are the indicator species of the aquatic environment. It is important that the species surveyed is not affected by humans. Dolphins are ideal as there is a strong dolphin taboo that means they are not hunted. The indigenous people feel they are almost human. There are tales of the dolphins sometimes taking on human form and stepping out of the water. It is said that they are very attracted to the young girls and make them pregnant. The dolphin population is very healthy, there are many and they are easy to count (well maybe not that easy as they pop up all over the place and so you don’t know whether you have already just counted it or whether it is a new one!) if anything is wrong with the aquatic environment, the dolphins will move away.

The survey method used is s line transect. The boat travels a set distance along the river between recorded points and the dolphins seen are recorded and their behaviour is observed. The data recorded includes species – pink or grey, GPS location, number in group, group composition (infant, juvenile, adult) and behaviour – feeding, travelling, resting, playing or mating (indicated by turning around with their nose out of the water with a stick held in their mouth, which we did observe.) 

The main difficulty was in knowing whether you had already counted the dolphin you had just seen, were there 3 dolphins you had seen twice or were there 6 individuals? Also, once you had encountered a group they would follow you and come along for the journey making it very difficult to know if and when you encountered a new group.

The wading bird survey indicates fish migrations and populations. There is little human pressure although sometimes the egrets are hunted and so this has to be noted. I enjoyed this survey very much but it was very difficult. The boat would slowly travel down river and any bird on a set list that was seen was recorded. Most of the birds I had never seen before so identification was the first problem. When there was one bird, such as a kingfisher flying past, that was no problem (other than knowing which kind of kingfisher it was) but when you were passing a stretch of trees along the river bank sheltering up to 20,000 cormorants all of which needed recording . . . . need I say more? 

We were looking for 23 species in all. All of these birds consume a massive amount of fish per day so the number of birds present indicates the fish presence.

The third indicator species survey was the macaw survey which is indicative of the forest environment. Macaws are fruit eaters. If the fruit crop is poor through problems with the forest environment the macaws will leave. Any significant drop in their numbers will be indicative of problems. The indigenous people do not have any effect on the population numbers as they do not hunt them.

The survey method used is a point count which is an abundance measure. Three species of macaws are recorded; red-bellied, blue-and-yellow and chestnut-breasted. The boat travels 500m along the river and then ties up for 15 minutes. Any macaws flying over are recorded. Macaws are very noisy and so are usually detected by sound before sight. They often fly very high so sound is also used to identify the species. The boat then moves 500m further along the river before again sitting for 15 minutes.

The resources species are animals used by the indigenous people. They need to be sustainable so it is important to keep data to help determine whether sustainability is being achieved and maintained.

Fish sustainability is measured in catch per unit effort. Fishing is undertaken in the same ways that the indigenous people use. A 30m long, 3m deep net with mesh of 3 inches is laid out for exactly one hour and then the catch is identified, measure, weighed, recorded and released. During this hour rod fishing is carried out using a 5 foot pole with 5 foot of line with a hook on the end. Again all the fish caught are identified, measured, weighed, recorded and released.

The second sustainability survey was for caiman. The caiman population has been greatly reduced through hunting but is now slowly recovering, although we saw very few and only small ones. There are three different caiman, black, smooth and spectacled. The caiman survey is carried out after dark. The boat covers a set distance, a spotlight being trained on the river’s edge to pick up reflections from the eyes of any caiman present. Once a caiman has been spotted the boat is brought into shore. If the caiman dives and swims away, the observer records the species and estimates the length. If the caiman is still there, it is caught by using a noose on the end of a pole. Once caught its jaws are taped closed. If it is large enough to be able to escape its legs are tied because if it were to escape with its jaws taped it would die. The data collected are species, weight, length, sex and GPS location.

The third sustainability survey was the terrestrial transect which is aimed at bush meat sustainability. There are set routes through the forest, about 3km in distance, which are walked at a pace of about 1km per hour, undergrowth and flooding allowing. Any animals sighted are recorded, the GPS location noted and the perpendicular distance from the track estimated.

Climate change

We had already experienced one effect of climate change, we were further up the river than we expected to be and as the water level didn’t drop we moved ever further up the river. As the Samiria-Pacaya National Park is an area of flooded forest, climate change can have a huge effect on both the animals and the people. During the dry season, large swathes of land become terrestrial which had been aquatic during the wet season. People, animals and plants rely on this, for instance, the turtles need the exposed beaches in the dry season for laying their eggs and the people use the exposed land for their crops. This year, as the water was unnaturally high, the turtles had so far been unable to lay any eggs. Data from animal observations and behaviour can add to the knowledge as to the effect climate change is having and to inform possible future mitigation.

The animal survey undertaken on this expedition was frogs. The survey was looking at the diversity of species in relation to habitat, type and season. The floating vegetation survey is undertaken after dark. The boat is driven hard onto a patch of floating vegetation (water hyacinth, river lettuce, grasses). With the aid of torches, frogs are collected from a 2m stretch along both sides of the boat. Each frog is photographed, identified, sexed if possible, weighed and measured before being released. The distance from the edge of the trees is recorded as is the distance from the boat and the height above the water surface. Each floating vegetation site is worked for 15 minutes.

Terrestrial frog transects are also undertaken in much the same way as the animal transects but the frogs are actively searched for into the leaf litter or the flooded areas. The same data are recorded.