Trends in Human Population in the Cook Islands

In looking at larger scale trends in environmental quality, we have pulled together population data over time across the Cook Islands. This is the overall trend (summing across all 15 of the islands that comprise the Cook Islands):

Cook Islands Population (all islands merged)

Here is a bit more complicated graph wherein an island representing each of the temporal patterns we have seen is plotted.  We have seen some islands that have a declining population since record-keeping began (1901; Palmerston), islands that peaked in the 1950s (e.g. Mauke), the 1960s (e.g. Nassau), 1970s (e.g. Aitutaki & Atiu), and now (e.g. Rarotonga).          

Cook Islands Population Trends<br>representative islands


You can find the absolute population numbers below.
Cook Islands 1902-2011 Population
These data were all sourced from the 2011 Cook Island Census.

Four species of crown-of-thorns

I wanted to toss up a quick post to clear up something we were talking about earlier in our trip.  We had several conversations earlier regarding the challenges of crown-of-thorn starfish (Acanthaster planci; often called simply “COTS”) surrounding their purported colonial nature.  This was a misconception.  The original stepping off point was the comment that this corallivorous echinoderm that has been decimating coral reefs across the Pacific for at least 70 years might indeed be some sort of amalgamation of four different organism.  The confusion spurred much debate while we were on Aitutaki and needs to be set straight.  It is not that a given individual is composed of four separate critters.  Rather, that what we have traditionally considered to be a single species is apparently four separate, identical-looking species.

COTS on a reef in Aitutaki Lagoon, August 2015

COTS on a reef in Aitutaki Lagoon, August 2015

Dead and desiccating crown-of-thron starfish at our Base 1 beach on Aitutaki.  July 29, 2015.  Killing individuals underwater can release larvae that bolster the population so the only sure way of killing these guys is to haul them up onto dry land and let them dry out in the air and sun.

Dead and desiccating crown-of-thorn starfish at our Base 1 beach on Aitutaki on July 29, 2015. Killing individuals underwater can release larvae that bolster the population. Hence the only sure way of killing these guys is to haul them up onto dry land and let them dry out in the war air and tropical sun.

See Vogler et al (2008) for the genetic data, but here is the upshot:

The distribution of four identified crown-of-thorns starfish species based on genetic markers (barcoding).  Figure from Vogler et al. 2008.

The distribution of four identified crown-of-thorns starfish species based on genetic markers (barcoding). Figure from Vogler et al. 2008.

From Vogler et al. 2008’s Introduction:

Coral reefs, the most species-rich marine ecosystems, are subjected to growing anthropogenic pressure, limiting their resilience to natural threats such as corallivorous predators (Bellwood et al. 2004).  Among those, the crown-of-thorns starfish (COTS) Acanthaster planci is infamous for its dramatic population explosions (called outbreaks) that have devastated coral reefs throughout the Indo-Pacific for decades, making it a major management issue (Birkeland & Lucas 1990Veron 2008).  But despite extensive research into COTS biology, the causes of outbreaks are still not clear; they probably involve a variable set of interacting natural and anthropogenic factors that lead to increased recruitment (Engelhardt & Lassig 1997).  An important consideration in both COTS research and management is that A. planci has been regarded as a single species throughout its distribution, and therefore the same ecological and behavioural traits are assumed worldwide.

Acanthaster planci‘s long-lived pelagic larva—surviving from three to four weeks in normal conditions (Yamaguchi 1973) to about seven weeks in marginal food regimes as found in oceanic conditions (Lucas 1982)—would be expected to promote genetic homogeneity.  But this species appears to be highly structured (Benzie 1999), in line with other recent studies of widespread marine invertebrates (e.g. Becker et al. 2007).  Using sequences of the mitochondrial cytochrome oxidase subunit I gene (COI) from samples covering its entire distribution, we show that A. planci consists of four deeply diverged clades that form a pan-Indo-Pacific species complex (as identified by DNA taxonomy; Vogler & Monaghan 2007).

And from their discussion:

Our discovery of four highly differentiated clades in one of the world’s most destructive coral predators has significant conservation implications.  Identifying cryptic speciation is essential to adequately study and contain species that require management (Bickford et al. 2007).  Although the status of A. planci is relatively poorly documented from the Indian Ocean and the Red Sea, outbreaks there do not appear to be as massive and widespread as in the Pacific (Zann 2000), suggesting that outbreak patterns might vary between the different sibling species.  Up to now, however, the overwhelming majority of COTS research has been performed in the Pacific.  Failure to recognize the existence of the sibling species could have contributed to a lack of understanding of the processes that lead to outbreaks in the different COTS lineages, by extrapolating results obtained from the Pacific studies to A. planci‘s entire distribution for both research and management purposes.

Future research will be required to investigate whether the life history, behavioural patterns and/or ecological requirements that may affect the outbreak dynamics of these four independent evolutionary COTS lineages have diverged sufficiently to necessitate lineage-specific management.  This could prove to be crucial for the design of appropriate management strategies to minimize the impact of future catastrophic COTS outbreaks in different regions of the world.

While still interesting, they are no chimera.

Symbolic of…something

I just got home and started bringing bags/equipment crates inside.  A turned to put my new CSUCI (aka CIinCI) hat on our hat rack and what did I see?  This:  

To the left is either my son’s or wife’s Koru Cafe hat we got last year and to the right is my “old school” CSUCI hat from circa 2006.  I think this symbolizes something, but I can’t quite figure it out in my exhaustion/unpacking stupor.  

I welcome interpretations of said hat rack.

I must be back in California…

Our New Orleans trips have a “getting home to SoCal” tradition.  Once we land at LAX (usually late at night), we hit the In-N-Out on Sepulveda for some burgers (preferably Animal Style) and fries.

Having just returned the good Dr. Lambrinos to LAX for his connecting flight up to Oregon I decided to make the ceremonial stop at the reigning temple of SoCal fast food culture.  This happened even though my family had just satiated John and me with drinks and food for the past few hours on a balcony in Manhattan Beach while we passed the hours of his layover.

Tradition are traditions afterall…Although it would have been nice to have one final pow-wow here in SoCal.

Heading Home

We are on our way home after two fantastic weeks of learning, service, all manner of interdisciplinary coastal monitoring and assessment, cultural exchange, and making tons of new friends.

Our internet credits have all expired, so we have been unable to post for the last day and a half, but check in the next few days for our pent up posts.

We had a wonderful final few days.  There were many watery eyes among our CI students and new Aitutaki friends alike as we held our final farewell to the Islands ceremony as the sun set on Aitutaki minutes before we boarded our plane to Rarotonga.

We will see everyone soon!

Second to last day…

Everyone is out and about today rushing to get as much done as we can before we head on back to the States tomorrow night.

Our Reef and Robotics Teams are on the boat, our Ciguatera Team is meeting with Dr. Helen at the hospital on their never-ending hunt for public health stats, and I have the Lagoon and Beach Teams with me near the airport.

Later today we have our meeting with the Island Council downtown.

Markets in the Morning

Our ciguatera team has been heading out most mornings (when their alarms go off) to census the offerings in the Aitutaki Market down at the main wharf on Sir Albert Henry Drive.  It opens at 6:00am and we usually shoot to get there around 6:20.  While have had an array of student make the drive into town with me, our most consistent stalwarts are Shannon (when her alarm works) and Aspen.  They have done a great job of both interviewing local folks about the understanding of the ciguatera situation (origins, historical trajectory, their own incidents of getting poisoned, etc.), trying to buy fish for our ciguatoxin assay, and surveying the local produce being offered.

Teaching the next Generation

On Tuesday, August 4 we were blessed with a visit by group of students from the local school here on Aitutaki.  These young people (who ranged from middle to high school ages) were in the middle of their two-week Independence Day holiday but still managed to muster up the energy to come by our “Base 1” (aka End of the Runway) site.  We (hopefully) regaled them with ecological stories and showed them various aspects of our monitoring efforts to characterize lagoon health.  After patiently sitting through our overview, they got down and dirty and helped with everything from our sand coring to looking for micro plastics in beach sand via our ESRM mobile microplastics lab.  They and their Araura College Principal Tracy Spiers (who we first met on last year’s preliminary visit to Aitutaki) had a fun time (we hope!).

Portable microplastics lab Base 1 08-04-15b

Our mobile ortable microplastics lab.

Araura College students learning how to search for and quantify microplastic particles in beach sand.

Araura College students learning how to search for and quantify microplastic particles in beach sand.


Sifting through core sand to hunt for invertebrates.

Sifting through core sand to hunt for invertebrates.

Coring at our Base 1 beach site.

Coring at our Base 1 beach site.

Tevin showing students a just-collected worm to our  Aitutaki students.

Tevin showing students a just-collected worm to our Aitutaki students.

Our CSUCI students had a great day showing the local kids how we do what we do.  The kids also taught us a thing or two (what it feels lilt to get ciguatera poisoning, etc.).  We hope to get them up and running with some subset of our lagoon monitoring protocols throughout the school year to help integrate more environmental science into their routine classes and simultaneously building a cadre to local Aitutaki folks into the routine monitoring we hope to foster here.