Invasion Ecology: Part II

Amy Hopkins and Nicole Cardona

Richard Henry Meinertzhagen

Thoughts?

Mineur et al 2007Hull fouling on commercial ships as a vector of macroalgal introduction

• Collected samples from commercial ships docking at Port Sete, France

• Goals:

• Determine if cargo ships hulls act as vectors for macroalgae in the present time

• Use direct evidence to determine vector status (previous studies have focused on presence of new species in a harbour vs. direct collection on a ship)

• Use in-water techniques to determine vector status (previous studies have used dry dock evidence)

• Catalogue species on hulls-”To address the gap in knowledge of the suspected role of hull fouling as a major vector of introduction of macroalgae during typical shipping activities, we sampled in a Mediterranean harbour to determine the species most frequently found attached to hulls of ocean-going cargo vessels.“

Location: Port Sete, commercial port on the Mediterranean coast of France, medium size port (1,035

ship entries in 2003)

Methods

• April to October 2003 (highest diversity expected due to ideal conditions)

• Ships sampled were registered with the International Maritime Organization

• Of the 22 hull, all had toxic coatings except one

• Species removed from hull with scraper, collected in a plankton net and located by eye

• Samples taken from three main areas on the hull: bow, stern and side that was not up against the port dock

Bow

Stern

Side (not facing port): waterline to 6m down

Sampling areas on hull

• If ships are from the same origin, should travel routes be taken into account?

• What about # of non-native species?

Results• 31 total taxa were found

• 77% of ships were found to be fouled by two to three taxa

• Most common biogeographical category of fouling taxa was cosmopolitan

• The ship with non-toxic coating had taxon richness six times greater than the mean found on toxic coated ships (probability of such an extreme result <0.001)

• Area of Origin did not influence the composition of fouling

• Hull length and Age of Coating did not influence the composition of fouling or taxon number

Biogeographical Categories

• Non-cosmopolitan: if they occur in only one biogeographical region or several adjacent ones

• Partially cosmopolitan: if they occur in several non-adjacent regions throughout the world

• Fully cosmopolitan: if they are found in the majority of the world’s biogeographical regions

• Is there enough information here in each category? Is it quantifiable?

Most Prevalent:

Ectocarpales and Ulvales

Ulva flexuosa

NC on Ship 8: Ceramiales

Antithamnion cruciatum Ceramium gaditanum

Future Considerations• The natural range of these species in unknown in many cases• Are natural ranges necessary or is any introduction something to be

eliminated?

• New shipping routes may open up due to global climate change, therefore affecting the potential of hull fouling as a vector

• Increased use of non-toxic coatings may cause for higher fouling rates (as shown by the vessel in this study) – further monitoring of vessel coating results is necessary

Questions

• Is the non-toxic alternative (Intersleek = silicon elastomer) really preferable to the toxic coating (TBT) if it may promote other environmental damages such as species introduction?

• What policies would you install regarding these findings?

• Design a controlled experiment to test performance of new coatings under realistic shipping regimes (speeds, emergsion/immersion cycles, etc)

Questions

• Should there be policies controlling ship docking and travel densities during the “increased taxa” months (April and May)?

• What economic implications do you see occurring as a consequence?

Questions• Compare and contrast methods and experimental design of the two

papers assigned this week and discuss which results are more useful and why.

• Does this experiment provide a good number of replicates? There are 22 total sampled hulls, consider that the port sees 1,035 ships per year.

• Does the subset of ships provide a good sample? The ships are all registered with the International Maritime Organization, they follow certain guidelines.

• The divers collecting samples were taking samples based on patches located by eye. Is there a problem with this? What kind of affect on the results might this have?

J. T. Carlton J . Hodder:Biogeography and dispersal of coastal marine organisms:

experimental studies on a replica of a 16th-century sailing vessel

• 16th century sailing vessels – from Yaquina Bay, Oregon to San Francisco Bay, CA – total of four bays

• Sampling: upon departure and arrival at each port

• Thesis: Shipping traffic may further play an important role in gene flow between isolated populations of obligate estuarine organisms, particularly those with non-planktonic larvae. Our intent was to measure the survival of fouling organisms as the vessel sailed from port to port.

Motivations for Research

• Accurate knowledge of human-mediated historical dispersal processes thus would be critical to many disciplines.

• These include: (1) biogeography, in terms of distinguishing between ancient natural and modern human-mediated dispersal; (2) evolution, in terms of understanding gene flow between otherwise-isolated populations (especially those taxa with non-planktonic life stages); and (3) ecology, in terms of understanding the historical origins of community diversity (the rate and timing of species insertions), knowledge fundamental to interpreting the evolutionary history of species co-occurrences.

No fouling except possibly green alga Enteromorpha sp.

Expected fouling in Yaquina: (1) en route from the mouth of the Columbia River to Tillamook Bay; (2) in Tillamook Bay; and (3) en route from Tillamook Bay to Yaquina Bay. On the keel and rudder half of two discrete clusters of mixed species fouling were removed.

Fouling Panels added. Eogammarus confervicolus and Parapleustes pugettensis hopped on since Yaquina Bay. Dendronotus frondosus fell off during Leg I.

Methods: Panels on GHII's rudder from Coos Bay were removed. Eight new vertical panels placed onto the rudder in the previous manner. Two racks with four vertical panels each were suspended from the floating pier 3 m from the vessel at a maximum depth of 2 m. These panels were deployed to compare settlement adjacent to the vessel, on the panels attached to the GHII, and on the GHII itself.

We removed for analysis in an alternating fashion four of the eight panels placed on the GHII's hull. In the spaces provided by the removed panels we inserted four new panels in order to assess in-transit settlement from Humboldt Bay to San Francisco Bay. In addition, we sampled the rudder and waterline of the vessel, the keel still being inaccessible. The dock fouling panels were removed and examined.

Leg I: Yaquina Bay to Coos Bay

Leg II: Coos Bay to Humboldt Bay

Leg III Humboldt Bay to San Francisco Bay

Dendronotus frondosus

DISTRIBUTIONBoreo-Arctic. In North Atlantic as far south as France (on European coast), and New Jersey (in North America). In North Pacific as far south as Los Angeles, California.

Grows to about 100mm. Juvenile animals feed on calyptoblastic hydroids such as Sertularia cupressina & Dynamena pumila while adults feed on the gymnoblastic hydroids of the genus Tubularia. The quite unrelated Indo-West Pacific aeolid Pteraeolidia ianthina has an identical change in diet from small colonial calyptoblastic hydroids to larger gymnoblastic tubularians.Taxonomically confused 'species'. Robilliard (1975) discusses the probability of at least 4 ecologically distinct species in NE Pacific.

http://seaslugforum.net/factsheet.cfm?base=dendfron

Eogammarus confervicolus

http://www.marinelifephotography.com/marine/arthropods/others/amphipods.htm

Of the 64 taxa found, 59 (92%) were transported to one or more ports. Similarly, there was little loss inoverall number of taxa, with 95, 90, and 92% surviving voyages of 1, 2, and 3 d, respectively.

Questions

Are the fouling panels a realistic scenario? Why/Why not?

Questions

Analyze these experimental methods. Are they objective enough? Are they well organized / is this a good design of the scientific method? Seems kind of scatter-brained to me . . .

On 28 August in Humboldt Bay the panels placed on the GHII's rudder in Coos Bay were removed. We initiated a second series of experiments by placing eight new vertical panels onto the rudder in the previons manner. The natural fouling on the rudder and waterline was sampled. The vessel was too close to the bottom to permit us to take samples from the keel. Two racks with four vertical panels each were suspended from the floating pier 3 m from the vessel at a maximum depth of 2 m. These panels were deployed to compare settlement adjacent to the vessel, on the panels attached to the GHII, and on the GHII itself.On 21 September we removed for analysis in an alternating fashion four of the eight panels placed on the GHII's hull on August 28. In the spaces provided by the removed panels we inserted four new panels in order to assess in-transit settlement from Humboldt Bay to San Francisco Bay. In addition, we sampled the rudder and waterline of the vessel, the keel still being inaccessible. The dock fouling panels were removed and examined. The GHII anchored for the night inside the bay's mouth and departed on the morning of 22 September for a 3-d voyage to San Francisco Bay.

Questions

What is the main difference between taxa found “naturally” on the ship and those on the panel?

Didn’t the species on the panel attach themselves naturally, also?

Questions

Are the fouling panels a realistic scenario? Why/Why not?

Questions

A working assumptionin biogeography is that the distribution of most organisms

along continental margins is natural, unless specific historicalevidence of changes in distribution is available. Do you agree?

Questions

What does this experiment mean to you? What would you do if you could use this evidence to create new policies? What other studies would you employ?

Questions

What is the difference in data collected from different parts of the ship? Would you have designed the experiment differently? Why/why not?

Questions

What are some of the margins of error overlooked by this research endeavor? How could you better control them?